ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller & Associates I MJW Corporation

Page 1 of 12

Document Title:

External Coworker Dosimetry Data for the 

X-10 Site 

Document Number: ORAUT-OTIB-0021

Revision: 01

Effective Date: 11/07/2006

Type of Document: OTIB

Supersedes: Revision 00

Subject Expert: Matthew H. Smith

Approval: Signature on File Approval Date: 10/24/2006

John M. Byrne, Document Owner

Concurrence: Signature on File Concurrence Date: 10/24/2006

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Concurrence Date: 10/24/2006

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 11/07/2006

James W. Neton, Associate Director for Science

 New Total Rewrite Revision Page Change

FOR DOCUMENTS MARKED AS A TOTAL REWRITE, REVISION, OR PAGE CHANGE, REPLACE THE PRIOR 

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 2 of 12

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

12/29/2004 00 New technical information bulletin to provide information to allow 

ORAU Team dose reconstructors to assign doses to workers at the 

X-10 site who have no or limited monitoring data, based on site 

coworker data. First approved issue. Initiated by Steven E. Merwin.

11/07/2006 01 Approved Revision 01 due to release of ORAUT-OTIB-0052, Rev. 

00. Per new document requirements, added a table of contents. 

This revision results in an increase in assigned dose and a PER is 

required. This revision also documents minor corrections to Table 2 

that do not require a PER. No further changes occurred as a result 

of formal internal review. Incorporates NIOSH formal review 

comments. Training required: As determined by the Task Manager. 

Initiated by Matthew H. Smith. 
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 3 of 12

TABLE OF CONTENTS

SECTION TITLE

1.0 PURPOSE ...............................................................................................................................

PAGE

5

2.0 BACKGROUND .......................................................................................................................5

3.0 GENERAL APPROACH...........................................................................................................5

4.0 APPLICATIONS AND LIMITATIONS .......................................................................................6

5.0 REFERENCES ........................................................................................................................7

6.0 X-10 COWORKER DATA DEVELOPMENT............................................................................. 7

7.0 X-10 COWORKER ANNUAL DOSE SUMMARIES .................................................................. 9

8.0 PENETRATING DOSE VALUES BASED ON OTIB-0052 GUIDANCE FOR SELECTED 

CONSTRUCTION TRADE WORKERS.................................................................................. 11

LIST OF TABLES

TABLE TITLE PAGE

1 Missed external doses based on X-10 external TBD................................................................ 8

2 Annual X-10 external coworker doses modified to account for missed dose........................... 10

3 Annual X-10 external penetrating coworker doses modified in accordance with 

ORAUT-OTIB-0052................................................................................................................ 11
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 4 of 12

ACRONYMS AND ABBREVIATIONS

CEDR Comprehensive Epidemiologic Data Resource

CER Center for Epidemiologic Research

DOE U.S. Department of Energy

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

IREP Interactive RadioEpidemiological Program

keV kilovolt-electron, 1,000 electron-volts

LODs limits of detection

mR millirad

mrem millirem

NIOSH National Institute for Occupational Safety and Health

NOCTS NIOSH-Office of Compensation Analysis and Support Claims Tracking System

ORAU Oak Ridge Associated Universities

TBD technical basis document

TIB technical information bulletin

U.S.C. United States Code

§ section or sections
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 5 of 12

1.0 PURPOSE

Technical information bulletins (TIBs) are not official determinations made by the National Institute for 

Occupational Safety and Health (NIOSH) but are rather general working documents that provide 

historic background information and guidance to assist in the preparation of dose reconstructions at 

particular sites or categories of sites. They will be revised in the event additional relevant information 

is obtained. TIBs may be used to assist NIOSH staff in the completion of individual dose 

reconstructions.

In this document the word “facility” is used as a general term for an area, building, or group of 

buildings that served a specific purpose at a site. It does not necessarily connote an “atomic weapons 

employer facility” or a “Department of Energy [DOE] facility” as defined in the Energy Employees 

Occupational Illness Compensation Program Act of 2000 (EEOICPA; 42 U.S.C. § 7384l(5) and (12)).

The purpose of this TIB is to provide information to allow dose reconstructors to assign doses to 

workers at the X-10 site who have no or limited monitoring data, based on site coworker data. The 

data in this TIB are to be used in conjunction with ORAUT-OTIB-0020, “Use of Coworker Dosimetry 

Data for External Dose Assignment.”1

2.0 BACKGROUND

The ORAU Team is conducting a series of coworker data studies to permit dose reconstructors to 

complete cases for which external and/or internal monitoring data are unavailable or incomplete. 

Such cases may fall into one of several categories, including:

• the worker was unmonitored and, even by today’s standards, did not need to be monitored 

(e.g., a non-radiological worker).

• the worker was unmonitored, but by today’s standards would have been monitored.

• the worker may have been monitored but the data are not available to the dose reconstructor.

• the worker may have partial information, but the available information is insufficient to permit a 

dose reconstruction to occur.

As described in the X-10 external dosimetry technical basis document (TBD),2 most workers with a 

potential for radiation exposure at the X-10 site wore radiation dosimetry badges, especially after 

1950. Also, the data provided to NIOSH in conjunction with this program are largely complete and 

sufficient for external dose reconstruction. Therefore, the coworker data provided in this TIB are 

expected to be of limited use for individuals who worked exclusively at the X-10 site. However, the 

specific work history is unknown for some individuals with no monitoring data who worked at more 

than one site within the Oak Ridge complex, and the data presented in this TIB will be a key 

component of dose reconstructions for some of those workers. 

3.0 GENERAL APPROACH

As described in ORAUT-OTIB-0020,1

 the general approach to applying coworker data for cases 

without external monitoring data involves two phases. The first phase (Phase I) permits cases to be 

processed when a “best and final” estimate of dose is not required for claim determination. The 

second phase (Phase II) of the external coworker data approach facilitates the assignment of “best 

and final estimates” of dose, when necessary. This initial revision of this TIB provides coworker 

external dosimetry summary statistics applicable to Phase I dose reconstructions; coworker dose 
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 6 of 12

distributions applicable to Phase II dose reconstructions will be made available in a subsequent 

revision. 

4.0 APPLICATIONS AND LIMITATIONS

1. Revision 1 of this document provides site coworker data and information that may be used only for 

cases not requiring best estimate calculations. Such cases include clearly non-compensable 

cases for which a higher external dose can be assigned than was likely to have been actually 

received, or clearly compensable cases for which a lower external dose can be assigned than was 

likely to have been actually received. Revision 1 of this document will provide dose distributions 

and additional information based on the data presented herein to permit the processing of cases 

requiring a best estimate analysis. 

2. At the Oak Ridge complex, many workers were employed at more than one of the major Oak 

Ridge sites (K-25, X-10, and Y-12). For some cases, employment information is provided in the 

NIOSH-Office of Compensation Analysis and Support Claims Tracking System as a multiple site 

listing, such as “K-25/Y-12/X-10,” and the available information, such as the DOE dosimetry 

records and claimant interview, are insufficient to determine the actual work location(s), especially 

on an annual basis. Similarly, workers may have worked at more than one major site at different 

locations across the DOE complex during their employment history. Thus, the data presented 

herein must be used with caution to ensure that for clearly non-compensable and compensable 

cases, unmonitored external doses from multiple site employment have been overestimated and 

underestimated, respectively.

3. Summary statistics based on X-10 dosimetry data presented in this TIB do not extend beyond 

1985 because reliable data were not available at the time this TIB was drafted. However, the 

absence of these data (and the subsequent development of dose distributions) should not 

interfere with the processing of most X-10 cases having a lack of external dosimetry data, since in 

recent years the monitoring practices at X-10 (and the other Oak Ridge sites) were sufficiently 

robust to ensure that essentially all workers with a potential for external radiation exposure were 

monitored. Should the need arise, and sufficient reliable data become available, coworker 

dosimetry data beyond the year 1985 will be presented in a subsequent revision to this TIB..

4. Summary statistics based on X-10 dosimetry data presented in this TIB do not extend beyond 

1985 because reliable data were not available at the time this TIB was drafted. However, the 

absence of these data (and the subsequent development of dose distributions) should not 

interfere with the processing of most X-10 cases having a lack of external dosimetry data, since in 

recent years the monitoring practices at X-10 (and the other Oak Ridge sites) were sufficiently 

robust to ensure that essentially all workers with a potential for external radiation exposure were 

monitored. Should the need arise, and sufficient reliable data become available, coworker 

dosimetry data beyond the year 1985 will be presented in a subsequent revision to this TIB.. 

5. The data presented in this TIB address penetrating radiation from gamma radiation and nonpenetrating radiation from beta radiation (and potentially low-energy photons). Neutron data are 

not presented. However, the locations within the X-10 site at which neutron exposures were 

possible are limited, and neutron doses were monitored separately for most workers having a 

potential for neutron exposure.2

 Therefore, it is not anticipated that the lack of coworker neutron 

dosimetry data in this TIB will negatively impact X-10 dose reconstructions. Coworker dosimetry 

data for neutron exposures will be presented in a subsequent revision to this TIB should the need 

arise and sufficient reliable data become available.
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 7 of 12

5.0 REFERENCES

1. ORAU Team, ORAUT-OTIB-0020, Rev. 00, Use of Coworker Dosimetry Data for External Dose 

Assignment, December 29, 2004.

2. ORAU Team, ORAUT-TKBS-0012-6, Rev. 00, Technical Basis Document for the Oak Ridge 

National Laboratory – Occupational External Dose, August 11, 2004.

3. NIOSH (National Institute for Occupational Safety and Health), External Dose Reconstruction

Implementation Guideline, Rev. 0, OCAS-IG-001, Office of Compensation Analysis and Support, 

Cincinnati, Ohio, 2002.

4. ORAU Team, ORAUT-OTIB-0052, Parameters to Consider When Processing Claims for 

Construction Trade Workers, Rev. 00, August 31, 2006.

6.0 X-10 COWORKER DATA DEVELOPMENT

Dosimetry data for monitored X-10 workers maintained by the Comprehensive Epidemiologic Data 

Resource (CEDR) maintained by DOE were selected for this evaluation. However, for the year 1966, 

data maintained by the ORAU Center for Epidemiologic Research (CER) were selected because 

CEDR data were not available for that year. The CEDR data evaluated represented quarterly or 

annual gamma and non-penetrating (“skin”) dosimetry data maintained by the X-10 site, which pertain 

to the shielded and open-window dosimetry readings and exclude neutron doses. Starting in 1961, 

the CEDR data are identified by quarter. Since the site implemented a quarterly badge exchange 

cycle for essentially all workers starting in the third quarter of 1956, these CEDR data are directly 

correlated to the X-10 site monitoring results. Prior to 1961, the CEDR data for X-10 typically include 

from one to three monitoring results each year for an individual. This is as indication that the result 

represents annual summaries of the quarterly or weekly (which was the typical exchange frequency 

prior to the third quarter of 1956) dosimetry data. The fact that two or three results are associated 

with some individuals is an indication that dosimetry results from Oak Ridge sites other than X-10 

(e.g., K-25 and Y-12) were included. It does not appear possible based on either the CEDR or CER 

data to separate the doses associated with the individual Oak Ridge sites prior to 1961; thus, these 

data should be used with caution by the dose reconstructors. 

The validity of the CEDR data (and CER data for 1966) was confirmed by comparing a random 

sampling of the data to claimant dosimetry data submitted by the site as part of the EEOICPA Subtitle 

B program. A review of data for ten claimants covering 253 combined-years of employment at X-10 

indicated generally good agreement between the two data sets. Specifically, the annual penetrating 

doses extracted from the two data sets matched perfectly in 92% and 74% of the 253 annual results 

for gamma and non-penetrating doses, respectively. Importantly, when the data did not match, the 

CEDR data were higher more than half of the time, suggesting that relying on the CEDR data for 

coworker dose reconstruction would not result in a negative bias against the claimants. Additionally, 

part of the mismatches were apparently attributable to quarterly doses that overlapped two calendar 

years being assigned two different years in the two data sets. Also, some of the instances in which 

the CEDR annual doses were less than the annual doses extracted from the EEOICPA claimant data 

were attributable to an occasional missing quarter of CEDR data; however, these instances do not 

result in an underestimation of coworker dose because of the extrapolation approach described in 

Section 7.0 below. Overall, the CEDR data (and CER data for 1966) are considered to be acceptable 

for the development of coworker doses for the X-10 site. 
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 8 of 12

Adjustment for Missed Dose

According to the External Dose Reconstruction Implementation Guideline,3 missed doses are to be 

assigned for null dosimeter readings to account for the possibility that doses were received but not 

recorded by the dosimeter or reported by the site. Annual missed doses are calculated by multiplying 

the number of null badge readings by the dosimeter limit of detection (LOD) and summing the results; 

these values are used as the 95th percentile of a lognormal distribution for the purpose of calculating 

probability of causation. Thus, in the Interactive Radioepidemiological Program (IREP) the calculated 

missed doses are multiplied by 0.5 and entered in Parameter 1, and a value of 1.52 is entered in 

Parameter 2, to represent the geometric mean and geometric standard deviation, respectively.

The assignment of missed doses for monitored workers is particularly significant for X-10 claimants 

because historically there are a high percentage of null dosimeter results for this site. By the 1980s 

more than 90% of quarterly penetrating dose readings and

Because X-10 claimants with null monitoring data are assigned missed dose, including those 

claimants who likely had no potential for external radiation exposure during their employment, the 

assignment of doses to workers with no monitoring data based on coworker data must also account 

for the assignment of missed dose.

reported annual doses were zero. By 

comparison, in the late 1950s, less than one-third of the quarterly results were zero. This is largely 

due to the site monitoring practices and the increasing robustness of radiological controls over time 

(starting in 1951, all regular workers wore a combination dosimeter and security badge regardless of 

work area - the transition to this system was completed by 1953).

Table 1 lists the maximum annual missed dose by era and type of radiation (penetrating gamma and 

non-penetrating) based on information presented in the site TBD.2

 Although the TBD indicates that 

some workers may have been on a dosimeter exchange cycle that was less or more frequent than the 

typical cycle, the great majority of workers were on the typical schedule so the values provided in 

Table 1 are deemed appropriate for the adjustment of reported coworker doses to account for missed 

dose.

Table 1. Missed external doses based on X-10 external TBD. 

Period

Penetrating 

LOD (rem)

Non-penetrating 

LOD (rem)a,b Exchange frequency

Maximum annual missed dose (rem)

Penetrating Non-penetrating

June 1944- June 1956 0.03 0.03 Weekly 1.560 1.560

July 1956 – 1974 0.03 0.03 Quarterly 0.120 0.120

1975 – present 0.01 0.01 Quarterly 0.040 0.040

a. Non-penetrating LODs are based on the TBD statement that “for assigning missed shallow dose, dose 

reconstructors should apply the deep dose values...unless there is reason to suspect exposure to a field 

consisting primarily of low-energy electrons.”2

b. The listed LODs are not reliable for low-energy beta particles. The X-10 TBD2 should be reviewed to identify 

potential exposure scenarios involving low-energy beta particles to determine whether the scenarios may apply 

to particular claimants. Note that cancer location is an important consideration, because beta particles with a 

low enough energy to render the tabulated LODs unreliable would deliver little dose through clothing.

Other Considerations

Certain aspects of the external dosimetry practices at the X-10 site documented in the TBD2 were 

considered in the analysis of the site data. These include:

• In some cases, values less than the dosimeter LOD were reported by the site. For example, 

values as low as 10 or 20 mR were reported even though the LOD was considered to be 30 

mrem (or 30 mR).
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 9 of 12

• Prior to 1951, dosimeter use was not expressly required for all workers – badges were 

typically provided only for people who entered the restricted area, and the badges were worn 

based on an “honor system” rather than a strict requirement. A review of claimant data 

indicates that most of these workers actually wore the badges when provided.

As described in Section 7.0 below, a favorable to claimant approach was adopted in the development 

of coworker dose summaries, and this approach should account for any underestimate of doses to 

radiological workers at the X-10 site based on the considerations described above.

7.0 X-10 COWORKER ANNUAL DOSE SUMMARIES 

Based on the information and approaches described above, X-10 coworker annual external dosimetry 

summaries were developed for use in the evaluation of external dose for claimants potentially 

exposed to workplace radiation, but with no monitoring data provided by DOE. These summaries 

were developed using the following steps:

1. As described in Section 6.0 above, the penetrating and “skin” doses available from CEDR (CER 

for 1966) were converted to annual data by summing the reported quarterly data (1961 and later) 

or summing the annual results that apparently cover the major Oak Ridge sites. Consistent with 

the guidelines in ORAUT-OTIB-0020,1 doses for individuals with less than four quarters of data for 

a particular year were converted to annual doses by extrapolating (i.e., one quarterly result was 

multiplied by 4; two quarterly results were multiplied by 2; and three quarterly results were 

multiplied by 1.333). Prior to 1961, reported doses were not extrapolated since the reported 

values apparently represented doses received during the entire year. 

2. The 50th, 95th and 99th percentile annual penetrating and skin doses were derived for two 

scenarios: excluding and including reported zeroes.

3. The 50th, 95th and 99th percentile doses based on the exclusion of zeroes were used as the 

basis for the coworker data set, since these are representative of radiological worker doses which 

are the principal focus of the coworker studies. However, to ensure favorability to the claimant, 

the percentile doses with zero results included were evaluated, and where the addition of one-half 

of the maximum annual missed doses (listed in Table 1) to these percentile doses resulted in 

values exceeding the percentile doses based on the exclusion of zeroes, the latter were replaced 

with the former.

4. The results are presented in Table 2 below. These percentile doses should be used for selected 

X-10 workers with no or limited monitoring data using the methodologies outlined in Section 7.0 of 

ORAUT-OTIB-0020.1

 

Dose to organs impacted only by penetrating radiation (e.g., organs other than the skin, breast and 

testes) are calculated based only on the “Gamma” columns in Table 2 combined with the appropriate 

organ dose conversion factors.3

 Doses to the skin, breast and testes (and any other cancer location 

potentially impacted by non-penetrating radiation) are determined based on both the “Gamma” and 

“Non-penetrating” columns; gamma doses are assigned as photons with energy ranges consistent 

with information in the external dosimetry TBD for the X-10 site,2 and non-penetrating doses are 

assigned as electrons >15 keV (or <30 keV photons if appropriate) with corrections applied to account 

for clothing attenuation or other relevant considerations. This approach explains why the occasional 

“zero” values in Table 2 for non-penetrating dose will not result in a dose of zero being assigned to an 

organ such as the skin. For example, the 50-th percentile dose to the skin in 1943 would be assigned 

entirely as 0.780 rem of photons.
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 10 of 12

The “zero” values for non-penetrating dose result from occurrences when the calculated missed 

doses (as described in Step 3 above) are used as the basis for the gamma and non-penetrating 

coworker doses; since the LODs are the same for both types of radiation (see Table 1), the 

subtraction of the two values results in a net non-penetrating dose of zero. This approach does not

Table 2. Annual X-10 external coworker doses modified to account 

for missed dose (rem).

result in an underestimation of dose because there cannot be missed dose for both penetrating and 

non-penetrating radiations at the LOD simultaneously without the open-window element recording a 

positive value (e.g., if the LOD is 30 mrem for both elements and a penetrating dose of 30 mrem is 

received in addition to a non-penetrating dose of 30 mrem), the open-window reading would 

effectively be twice the LOD, or 60 mrem). Additionally, assigning beta dose as gamma dose in IREP 

has no negative effect because the radiation effectiveness factors are the same for >15 keV electrons 

and >250 keV photons, and are higher for both <30 keV photons and 30-250 keV photons. 

Year

Gamma

99th%

Gamma

95th%

Gamma

50th%

Non-pen

99th%

Non-pen

95th%

Non-pen

50th%

1943 1.762 1.370 0.780 0.000 0.000 0.000

1944 3.861 2.810 0.915 0.507 0.235 0.025

1945 2.950 1.465 0.780 4.559 1.325 0.000

1946 2.501 1.373 0.780 6.947 3.895 0.000

1947 3.363 1.329 0.780 5.286 2.030 0.000

1948 2.564 1.290 0.780 4.593 0.835 0.030

1949 3.999 2.542 0.780 4.595 2.340 0.000

1950 3.113 1.604 0.780 3.967 2.003 0.000

1951 4.356 2.585 0.780 5.163 2.970 0.000

1952 6.131 3.750 0.780 5.303 2.881 0.040

1953 5.081 2.539 0.800 4.821 2.632 0.045

1954 5.508 2.206 0.780 8.202 3.244 0.070

1955 4.686 2.541 0.820 8.119 4.649 0.073

1956 4.550 2.161 0.470 3.996 1.592 0.040

1957 5.463 2.035 0.180 4.303 1.796 0.195

1958 3.156 1.610 0.320 3.249 1.087 0.195

1959 3.600 1.788 0.270 3.456 1.329 0.090

1960 2.879 1.304 0.110 2.401 0.936 0.055

1961 2.020 0.980 0.100 1.061 0.312 0.030

1962 2.268 1.020 0.110 1.479 0.570 0.047

1963 2.030 1.006 0.120 1.200 0.412 0.030

1964 2.067 0.904 0.090 1.397 0.502 0.030

1965 2.371 1.220 0.080 1.729 0.764 0.060

1966 2.816 1.230 0.080 3.824 0.740 0.070

1967 2.828 1.360 0.110 2.234 0.905 0.078

1968 2.669 1.302 0.100 2.501 0.649 0.050

1969 2.302 1.192 0.110 2.035 0.526 0.050

1970 1.850 1.029 0.100 2.190 0.562 0.050

1971 2.109 1.100 0.090 1.795 0.442 0.030

1972 2.435 1.386 0.100 3.976 0.614 0.010

1973 2.238 1.210 0.080 2.107 0.290 0.030

1974 1.485 0.750 0.060 0.949 0.116 0.010

1975 2.080 1.188 0.090 1.825 0.450 0.000

1976 1.992 1.121 0.060 0.515 0.122 0.000

1977 2.356 0.980 0.060 0.290 0.128 0.000

1978 1.901 1.021 0.100 0.440 0.202 0.000

1979 1.977 1.194 0.100 0.638 0.349 0.000
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 11 of 12

1980 2.312 1.269 0.080 3.071 0.466 0.000

1981 1.954 1.176 0.160 1.594 0.968 0.040

1982 1.612 1.030 0.180 2.058 0.606 0.070

1983 1.829 1.237 0.250 2.181 0.781 0.045

1984 1.740 0.949 0.175 1.609 0.450 0.045

1985 1.300 0.940 0.170 1.396 0.279 0.070

8.0 PENETRATING DOSE VALUES BASED ON OTIB-0052 GUIDANCE FOR SELECTED 

CONSTRUCTION TRADE WORKERS

Table 3 contains penetrating dose values that have been adjusted using the guidance given in 

Section 8.0 of ORAUT-OTIB-0052, “Parameters to Consider When Processing Claims for 

Construction Trade Workers.”4

 This guidance is applicable for construction trade workers who meet 

the criteria given in Section 3.0 of ORAUT-OTIB-0052.4

Table 3. Annual X-10 external penetrating coworker doses 

modified in accordance with ORAUT-OTIB-0052 (rem).

Year

Gamma

99th%

Gamma

95th%

Gamma

50th%

1943 2.155 1.606 0.780

1944 5.093 3.622 0.969

1945 4.129 1.739 0.780

1946 3.190 1.811 0.780

1947 4.708 1.860 0.780

1948 3.589 1.494 0.780

1949 5.599 3.559 0.780

1950 4.172 2.246 0.780

1951 6.098 3.619 0.780

1952 8.584 5.250 0.780

1953 6.951 3.554 0.808

1954 7.711 3.089 0.780

1955 6.485 3.557 0.836

1956 6.370 3.025 0.490

1957 7.648 2.849 0.228

1958 4.418 2.233 0.424

1959 5.040 2.504 0.354

1960 4.031 1.826 0.130

1961 2.828 1.372 0.116

1962 3.152 1.404 0.130

1963 2.818 1.387 0.144

1964 2.870 1.254 0.102

1965 3.319 1.708 0.098

1966 3.942 1.722 0.112

1967 3.959 1.904 0.154

1968 3.736 1.822 0.140

1969 3.222 1.668 0.154

1970 2.590 1.440 0.140

1971 2.952 1.540 0.126

1972 3.409 1.940 0.140

1973 3.134 1.694 0.112

1974 2.079 1.050 0.070

1975 2.912 1.663 0.126

1976 2.788 1.569 0.084

1977 3.298 1.372 0.084

1978 2.661 1.429 0.140
Document No. ORAUT-OTIB-0021 Revision No. 01 Effective Date: 11/07/2006 Page 12 of 12

1979 2.768 1.671 0.140

1980 3.237 1.777 0.112

1981 2.736 1.646 0.224

1982 2.257 1.442 0.252

1983 2.561 1.731 0.350

1984 2.435 1.328 0.245

1985 1.820 1.316 0.238