Company monitors the creditworthiness of its counterparties and believes that losses from nonperformance are unlikely to occur.
Hedging gains and losses related to the Company’s crude oil and natural gas production are recorded in oil and gas sales and royalties.
During 2005, 2004 and 2003, the Company recognized a reduction of revenues of $237.7 million, $61.3 million and $67.5 million related to its cash flow hedges in oil and gas sales and royalties.
See ‘‘Item 7A.
Quantitative and Qualitative Disclosures About Market Risk – Commodity Price Risk.
’’ Costs and Expenses Production Costs – Production costs, from continuing operations, consisting of lease operating expense, workover expense, production and ad valorem taxes and transportation costs increased $112.4 million, or 56%, in 2005 compared to 2004.
The increase was due to higher production volumes attributed to newlyacquired Patina properties and to higher per-unit production and ad valorem taxes.
Production costs increased $39.3 million, or 24%, in 2004 compared to 2003.
The increase was due to new operations in Israel, increased production from the ramp-up of Phase 2A in Equatorial Guinea and new production in the Gulf of Mexico.
Other factors affecting operations expense included increased service costs and workovers.
The table below includes the crude oil and natural gas production costs from continuing operations by area for the last three years.
## Table 0 ##
(1) Lease operating expense includes labor, fuel, repairs, replacements, saltwater disposal and other related lifting costs.
(2) Sales began in first quarter 2004.
(3) Other international includes Ecuador, China and Argentina.
Table of Contents Index to Financial Statements 73 (2) West Africa includes Equatorial Guinea, Cameroon and Gabon.
(3) Other International, Corporate includes the Falkland Islands, Suriname and other new ventures and corporate expenditures.
(4) For a discussion of 2016 dry hole cost, see Items 1.  and 2.  Business and Properties – International – West Africa and Item 8.
Financial Statements and Supplementary Data – Note 6.
Capitalized Exploratory Well Costs.
(5) Includes lease rental and other exploration expense.
Exploration expense for 2016 included: ?
leasehold impairment expense including the write-off of leases and licenses of $58 million for the deepwater Gulf of Mexico, $25 million for the Falkland Islands and $10 million for other onshore US; ?
dry hole cost including costs related to the Silvergate exploratory well, deepwater Gulf of Mexico, the Dolphin 1 natural gas discovery, offshore Israel, and certain discoveries offshore West Africa; ?
seismic expense relating to the acquisition of 3D seismic data in West Africa and other international areas; ?
other cost for onshore US including lease rentals primarily related to Permian Basin leases; and ?
salaries and related expenses for corporate exploration and new ventures personnel.
Oil and gas exploration expense decreased in 2015 as compared with 2014.
Expense for 2015 includes the following: ?
leasehold impairment expense including the write-off of our northeast Nevada leases of $21 million; ?
US dry hole cost including amounts related to northeast Nevada exploration efforts which we elected to discontinue after assessing commercial viability in the current commodity price environment; ?
West Africa dry hole cost including the Cheetah well (offshore Cameroon) and Other International dry hole cost including the Humpback well (offshore Falkland Islands), neither of which identified commercial quantities of hydrocarbons; and ?
salaries and related expenses for corporate exploration and new ventures personnel.
Exploration expense included stock-based compensation expense of $10 million in 2016, $13 million in 2015 and $17 million in 2014.
Depreciation, Depletion and Amortization DD&A expense was as follows:
## Table 1 ##
(1) DD&A expense includes accretion of discount on asset retirement obligations of $48 million in 2016, $43 million in 2015, and $36 million in 2014.
(2) Consolidated unit rates exclude sales volumes and costs attributable to equity method investees.
Total DD&A expense increased for 2016 as compared with 2015 due to the following: ?
increase of $178 million related to higher sales volumes resulting from commencement of production from the Big Bend, Dantzler and Gunflint development projects in deepwater Gulf of Mexico in 2016 and 2015; ?
increase of $134 million related to the acquisition of Eagle Ford Shale and Permian Basin production third quarter 2015; and ?
$121 million related to the reduction in proved reserves in fourth quarter 2015 primarily due to downward price revisions in DJ Basin and Marcellus Shale; partially offset by: ?
an overall lower segment rate for offshore Equatorial Guinea due to the fluctuation in production from higher DD&A rate assets Aseng and Alen to lower DD&A rate asset Alba field.
The decrease in the unit rate per BOE for 2016 as compared with 2015 was due primarily to lower-cost production volumes from the Tamar and Alba fields and net book value impairments in fourth quarter 2015 mainly due to downward commodity price revisions.
The decrease in the unit rate per BOE was partially offset by increased higher-cost production volumes from certain onshore US properties and recently commenced production from deepwater Gulf of Mexico assets, including Big Bend, Dantzler and Gunflint.
Our tax returns are currently under examination in various foreign jurisdictions.
The major foreign tax jurisdictions under examination include Germany, Italy and Switzerland.
It is reasonably possible that such audits will be resolved in the next twelve months, but we do not anticipate that the resolution of these audits would result in any material impact on our results of operations or financial position.12.
CAPITAL STOCK AND EARNINGS PER SHARE We have 2 million shares of Series A Participating Cumulative Preferred Stock authorized for issuance, none of which were outstanding as of December 31, 2007.
The numerator for both basic and diluted earnings per share is net earnings available to common stockholders.
The denominator for basic earnings per share is the weighted average number of common shares outstanding during the period.
The denominator for diluted earnings per share is weighted average shares outstanding adjusted for the effect of dilutive stock options and other equity awards.
The following is a reconciliation of weighted average shares for the basic and diluted share computations for the years ending December 31 (in millions):
## Table 2 ##
For the year ended December 31, 2007, an average of 3.1 million options to purchase shares of common stock were not included in the computation of diluted earnings per share as the exercise prices of these options were greater than the average market price of the common stock.
For the years ended December 31, 2006 and 2005, an average of 7.6 million and 2.9 million options, respectively, were not included.
In December 2005, our Board of Directors authorized a stock repurchase program of up to $1 billion through December 31, 2007.
In December 2006, our Board of Directors authorized an additional stock repurchase program of up to $1 billion through December 31, 2008.
As of December 31, 2007 we had acquired approximately 19,345,200 shares at a cost of $1,378.9 million, before commissions.13.
SEGMENT DATA We design, develop, manufacture and market reconstructive orthopaedic implants, including joint and dental, spinal implants, trauma products and related orthopaedic surgical products which include surgical supplies and instruments designed to aid in orthopaedic surgical procedures and post-operation rehabilitation.
We also provide other healthcare related services.
Revenue related to these services currently represents less than 1 percent of our total net sales.
We manage operations through three major geographic segments – the Americas, which is comprised principally of the United States and includes other North, Central and South American markets; Europe, which is comprised principally of Europe and includes the Middle East and Africa; and Asia Pacific, which is comprised primarily of Japan and includes other Asian and Pacific markets.
This structure is the basis for our reportable segment information discussed below.
Management evaluates operating segment performance based upon segment operating profit exclusive of operating expenses pertaining to global operations and corporate expenses, share-based compensation expense, settlement, acquisition, integration and other expenses, inventory step-up, in-process research and development writeoffs and intangible asset amortization expense.
Global operations include research, development engineering, medical education, brand management, corporate legal, finance, and human resource functions, and U. S.  and Puerto Rico based manufacturing operations and logistics.
Intercompany transactions have been eliminated from segment operating profit.
Management reviews accounts receivable, inventory, property, plant and equipment, goodwill and intangible assets by reportable segment exclusive of U.
S and Puerto Rico based manufacturing operations and logistics and corporate assets.

<table><tr><td> </td><td><i>Total</i> </td><td><i>United States</i> </td><td><i>Equatorial Guinea</i> </td><td><i>North Sea</i> </td><td><i>Israel<sup>-2</sup></i> </td><td><i>Corporate & Other Int'l<sup>-3</sup></i> </td></tr><tr><td> </td><td colspan="6">(in thousands) </td></tr><tr><td> Year Ended December 31, 2005</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Lease operating<sup>-1</sup></td><td>$203,833</td><td>$136,087</td><td>$30,661</td><td>$12,244</td><td>$8,504</td><td>$16,337</td></tr><tr><td>Workover expense</td><td>14,027</td><td>13,734</td><td>–</td><td>259</td><td>–</td><td>34</td></tr><tr><td>Total operations expense</td><td>217,860</td><td>149,821</td><td>30,661</td><td>12,503</td><td>8,504</td><td>16,371</td></tr><tr><td>Production and ad valorem</td><td>78,703</td><td>65,428</td><td>–</td><td>–</td><td>–</td><td>13,275</td></tr><tr><td>Transportation expense</td><td>16,764</td><td>9,350</td><td>–</td><td>6,562</td><td>–</td><td>852</td></tr><tr><td>Total production costs</td><td>$313,327</td><td>$224,599</td><td>$30,661</td><td>$19,065</td><td>$8,504</td><td>$30,498</td></tr><tr><td>  Year Ended December 31, 2004</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Lease operating<sup>-1</sup></td><td>$136,471</td><td>$85,013</td><td>$20,811</td><td>$8,803</td><td>$7,203</td><td>$14,641</td></tr><tr><td>Workover expense</td><td>16,635</td><td>16,635</td><td>–</td><td>–</td><td>–</td><td>–</td></tr><tr><td>Total operations expense</td><td>153,106</td><td>101,648</td><td>20,811</td><td>8,803</td><td>7,203</td><td>14,641</td></tr><tr><td>Production and ad valorem</td><td>28,022</td><td>21,806</td><td>–</td><td>–</td><td>–</td><td>6,216</td></tr><tr><td>Transportation expense</td><td>19,808</td><td>8,631</td><td>–</td><td>10,480</td><td>–</td><td>697</td></tr><tr><td>Total production costs</td><td>$200,936</td><td>$132,085</td><td>$20,811</td><td>$19,283</td><td>$7,203</td><td>$21,554</td></tr><tr><td>  Year Ended December 31, 2003</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Lease operating<sup>-1</sup></td><td>$111,724</td><td>$72,107</td><td>$13,441</td><td>$8,453</td><td>$–</td><td>$17,723</td></tr><tr><td>Workover expense</td><td>6,303</td><td>6,303</td><td>–</td><td>–</td><td>–</td><td>–</td></tr><tr><td>Total operations expense</td><td>118,027</td><td>78,410</td><td>13,441</td><td>8,453</td><td>–</td><td>17,723</td></tr><tr><td>Production and ad valorem</td><td>22,722</td><td>17,850</td><td>–</td><td>–</td><td>–</td><td>4,872</td></tr><tr><td>Transportation expense</td><td>20,888</td><td>10,877</td><td>–</td><td>9,024</td><td>–</td><td>987</td></tr><tr><td>Total production costs</td><td>$161,637</td><td>$107,137</td><td>$13,441</td><td>$17,477</td><td>$–</td><td>$23,582</td></tr></table>
<table><tr><td></td><td colspan="3">Year Ended December 31,</td></tr><tr><td>(millions, except unit rate)</td><td>2016</td><td>2015</td><td>2014</td></tr><tr><td>United States</td><td>$2,122</td><td>$1,692</td><td>$1,318</td></tr><tr><td>Israel</td><td>81</td><td>70</td><td>63</td></tr><tr><td>Equatorial Guinea</td><td>205</td><td>326</td><td>299</td></tr><tr><td>Other International, and Corporate</td><td>46</td><td>43</td><td>79</td></tr><tr><td>Total DD&A Expense<sup>-1</sup></td><td>$2,454</td><td>$2,131</td><td>$1,759</td></tr><tr><td>Unit Rate per BOE<sup>-2</sup></td><td>$16.26</td><td>$16.75</td><td>$16.55</td></tr></table>
<table><tr><td></td><td>2007</td><td>2006</td><td>2005</td></tr><tr><td>Weighted average shares outstanding for basic net earnings per share</td><td>235.5</td><td>243.0</td><td>247.1</td></tr><tr><td>Effect of dilutive stock options and other equity awards</td><td>2.0</td><td>2.4</td><td>2.7</td></tr><tr><td>Weighted average shares outstanding for diluted net earnings per share</td><td>237.5</td><td>245.4</td><td>249.8</td></tr></table>

Question: Which year is transportation expense in total the highest?