## Table 0 ##
[a] None of the credit facility was used as of December 31, 2012.
[b] $100 million of the receivables securitization facility was utilized at December 31, 2012, which is accounted for as debt.
The full program matures in July 2013.
[c] Includes guaranteed obligations related to our headquarters building, equipment financings, and affiliated operations.
[d] None of the letters of credit were drawn upon as of December 31, 2012.
Off-Balance Sheet Arrangements Guarantees – At December 31, 2012, we were contingently liable for $307 million in guarantees.
We have recorded a liability of $2 million for the fair value of these obligations as of December 31, 2012 and 2011.
We entered into these contingent guarantees in the normal course of business, and they include guaranteed obligations related to our headquarters building, equipment financings, and affiliated operations.
The final guarantee expires in 2022.
We are not aware of any existing event of default that would require us to satisfy these guarantees.
We do not expect that these guarantees will have a material adverse effect on our consolidated financial condition, results of operations, or liquidity.
OTHER MATTERS Labor Agreements – Approximately 86% of our 45,928 full-time-equivalent employees are represented by 14 major rail unions.
During the year, we concluded the most recent round of negotiations, which began in 2010, with the ratification of new agreements by several unions that continued negotiating into 2012.
All of the unions executed similar multi-year agreements that provide for higher employee cost sharing of employee health and welfare benefits and higher wages.
The current agreements will remain in effect until renegotiated under provisions of the Railway Labor Act.
The next round of negotiations will begin in early 2015.
Inflation – Long periods of inflation significantly increase asset replacement costs for capital-intensive companies.
As a result, assuming that we replace all operating assets at current price levels, depreciation charges (on an inflation-adjusted basis) would be substantially greater than historically reported amounts.
Derivative Financial Instruments – We may use derivative financial instruments in limited instances to assist in managing our overall exposure to fluctuations in interest rates and fuel prices.
We are not a party to leveraged derivatives and, by policy, do not use derivative financial instruments for speculative purposes.
Derivative financial instruments qualifying for hedge accounting must maintain a specified level of effectiveness between the hedging instrument and the item being hedged, both at inception and throughout the hedged period.
We formally document the nature and relationships between the hedging instruments and hedged items at inception, as well as our risk-management objectives, strategies for undertaking the various hedge transactions, and method of assessing hedge effectiveness.
Changes in the fair market value of derivative financial instruments that do not qualify for hedge accounting are charged to earnings.
We may use swaps, collars, futures, and/or forward contracts to mitigate the risk of adverse movements in interest rates and fuel prices; however, the use of these derivative financial instruments may limit future benefits from favorable price movements.
Market and Credit Risk – We address market risk related to derivative financial instruments by selecting instruments with value fluctuations that highly correlate with the underlying hedged item.
We manage credit risk related to derivative financial instruments, which is minimal, by requiring high credit standards for counterparties and periodic settlements.
At December 31, 2012 and 2011, we were not required to provide collateral, nor had we received collateral, relating to our hedging activities.
Proven, or measured, reserves are those reserves for which the quantity is computed from dimensions revealed by drill data, together with other direct and measurable observations such as outcrops, trenches and quarry faces.
The grade and quality of those reserves are computed from the results of detailed sampling, and the sampling and measurement data are spaced so closely and the geologic character is so well defined that size, shape, depth and mineral content of reserves are well established.
Probable, or indicated, reserves are those reserves for which quantity and grade and quality are computed partly from specific measurements and partly from projections based on reasonable, though not drilled, geologic evidence.
The degree of assurance, although lower than that for proven reserves, is high enough to assume continuity between points of observation.
Reported proven and probable reserves include only quantities that are owned in fee or under lease, and for which all appropriate zoning and permitting have been obtained.
Leases, zoning, permits, reclamation plans and other government or industry regulations often set limits on the areas, depths and lengths of time allowed for mining, stipulate setbacks and slopes that must be left in place, and designate which areas may be used for surface facilities, berms, and overburden or waste storage, among other requirements and restrictions.
Our reserves estimates take into account these factors.
Technical and economic factors also affect the estimates of reported reserves regardless of what might otherwise be considered proven or probable based on a geologic analysis.
For example, excessive overburden or weathered rock, rock quality issues, excessive mining depths, groundwater issues, overlying wetlands, endangered species habitats, and rights of way or easements may effectively limit the quantity of reserves considered proven and probable.
In addition, computations for reserves in-place are adjusted for estimates of unsaleable sizes and materials as well as pit and plant waste.
The 15.0 billion tons of estimated aggregates reserves reported at the end of 2011 include reserves at inactive and greenfield (undeveloped) sites.
We reported proven and probable reserves of 14.7 billion tons at the end of 2010 using the same basis.
The table below presents, by division, the tons of proven and probable aggregates reserves as of December 31, 2011 and the types of facilities operated.
## Table 1 ##
In addition to the facilities included in the table above, we operate 22 recrushed concrete plants which are not dependent on reserves.
Of the 15.0 billion tons of aggregates reserves, 8.6 billion tons or 58% are located on owned land and 6.4 billion tons or 42% are located on leased land.
While some of our leases run until reserves at the leased sites are exhausted, generally our leases have definite expiration dates, which range from 2012 to 2159.
Most of our leases have renewal options to extend them well beyond their current terms at our discretion.
Changes to the assumptions listed above would have an impact on the projected benefit obligations, the accrued other postretirement benefit liabilities, and the annual net periodic pension and other postretirement benefit cost.
The following table reflects the favorable and unfavorable outcomes associated with a change in certain assumptions:
## Table 2 ##
As of December 31, 2008, our Master Pension Trust had assets invested at Westridge Capital Management, Inc.  (WCM) with a reported fair value of $59.2 million.
In February 2009, the New York District Court appointed a receiver over WCM due to allegations of fraud and other violations of federal commodities and securities laws by principals of a WCM affiliate.
In light of these allegations, we reassessed the fair value of our investments at WCM and recorded a $48.0 million write-down in the estimated fair value of these assets for the year ended December 31, 2008.
During 2011, the fair value of assets increased from $630.3 million to $636.6 million due primarily to the recovery of an additional $22.0 million from WCM’s court-appointed receiver.
This recovery resulted in the recognition of a $10.8 million return on plan assets (net of the $11.2 million remaining WCM investment).
During 2010, WCM receipts included a $6.6 million release from the receiver as a partial distribution and a $15.0 million insurance settlement for the loss.
During 2012, we expect to recognize net periodic pension expense of approximately $37.0 million and net periodic postretirement expense of approximately $11.6 million compared to $25.7 million and $11.7 million, respectively, in 2011.
The increase in pension expense is due primarily to the decrease in the discount rate and the change to reflect generational mortality improvement.
For the qualified pension plans, the increase in pension expense is also due to lower than expected asset returns in 2011.
As a result of our 2010 pension contributions of $72.5 million in March and $1.3 million in July, we do not expect to make any contributions to the funded pension plans during 2012.
Assuming actuarial assumptions are realized, existing funding credit balances are sufficient to fund projected minimum required contributions through 2012.
We currently do not anticipate that the funded status of any of our plans will fall below statutory thresholds requiring accelerated funding or constraints on benefit levels or plan administration.
For additional information regarding pension and other postretirement benefits, see Note 10 "Benefit Plans" in Item 8 "Financial Statements and Supplementary Data. "5.
ENVIRONMENTAL COMPLIANCE Our environmental compliance costs include the cost of ongoing monitoring programs, the cost of remediation efforts and other similar costs.
HOW WE ACCOUNT FOR ENVIRONMENTAL COSTS To account for environmental costs, we: ?
expense or capitalize environmental costs consistent with our capitalization policy ?
expense costs for an existing condition caused by past operations that do not contribute to future revenues ?
accrue costs for environmental assessment and remediation efforts when we determine that a liability is probable and we can reasonably estimate the cost
FEDERAL REALTY INVESTMENT TRUST SCHEDULE III SUMMARY OF REAL ESTATE AND ACCUMULATED DEPRECIATION—CONTINUED Three Years Ended December 31, 2006 Reconciliation of Accumulated Depreciation and Amortization (in thousands)
## Table 3 ##
The following table sets forth the schedule of lease expirations for our commercial leases in place as of December 31, 2017 for each of the 10 years beginning with 2018 and after 2027 in the aggregate assuming that none of the tenants exercise future renewal options.

Tables referenced above, in order (Table 0 first):
<table><tr><td></td><td></td><td><i>Amount of Commitment Expiration per Period</i></td></tr><tr><td><i>Other Commercial Commitments</i><i>Millions</i></td><td><i>Total</i></td><td><i>2013</i></td><td><i>2014</i></td><td><i>2015</i></td><td><i>2016</i></td><td><i>2017</i></td><td><i>After 2017</i></td></tr><tr><td>Credit facilities [a]</td><td>$1,800</td><td>$-</td><td>$-</td><td>$1,800</td><td>$-</td><td>$-</td><td>$-</td></tr><tr><td>Receivables securitization facility [b]</td><td>600</td><td>600</td><td>-</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Guarantees [c]</td><td>307</td><td>8</td><td>214</td><td>12</td><td>30</td><td>10</td><td>33</td></tr><tr><td>Standby letters of credit [d]</td><td>25</td><td>24</td><td>1</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>Total commercialcommitments</td><td>$2,732</td><td>$632</td><td>$215</td><td>$1,812</td><td>$30</td><td>$10</td><td>$33</td></tr></table>
<table><tr><td></td><td colspan="4"><i>Number of Aggregates Operating Facilities<sup>1</sup></i></td></tr><tr><td></td><td><i>Reserves (billions of tons)</i></td><td><i>Stone</i></td><td><i>Sand and Gravel</i></td><td><i>Sales Yards</i></td></tr><tr><td> By Division:</td><td></td><td></td><td></td><td></td></tr><tr><td>Florida Rock</td><td>0.5</td><td>7</td><td>11</td><td>7</td></tr><tr><td>Mideast</td><td>3.7</td><td>37</td><td>2</td><td>23</td></tr><tr><td>Midsouth</td><td>2.2</td><td>43</td><td>1</td><td>0</td></tr><tr><td>Midwest</td><td>1.8</td><td>14</td><td>3</td><td>3</td></tr><tr><td>Southeast</td><td>2.6</td><td>34</td><td>0</td><td>3</td></tr><tr><td>Southern & Gulf Coast</td><td>2.3</td><td>27</td><td>1</td><td>30</td></tr><tr><td>Southwest</td><td>0.9</td><td>14</td><td>1</td><td>11</td></tr><tr><td>Western</td><td>1.0</td><td>3</td><td>24</td><td>2</td></tr><tr><td> Total</td><td> 15.0</td><td> 179</td><td> 43</td><td> 79</td></tr></table>
<table><tr><td></td><td colspan="4">(Favorable) Unfavorable</td></tr><tr><td></td><td colspan="2">0.5 Percentage Point Increase</td><td colspan="2">0.5 Percentage Point Decrease</td></tr><tr><td><i>in millions</i></td><td>Inc (Dec) in Benefit Obligation</td><td>Inc (Dec) in Benefit Cost</td><td>Inc (Dec) in Benefit Obligation</td><td>Inc (Dec) in Benefit Cost</td></tr><tr><td> Actuarial Assumptions</td><td></td><td></td><td></td><td></td></tr><tr><td>Discount rate</td><td></td><td></td><td></td><td></td></tr><tr><td>Pension</td><td>-$54.0</td><td>-$5.1</td><td>$60.3</td><td>$5.6</td></tr><tr><td>Other postretirement benefits</td><td>-5.1</td><td>-0.2</td><td>5.5</td><td>0.3</td></tr><tr><td>Expected return on plan assets</td><td>not applicable</td><td>-3.1</td><td>not applicable</td><td>3.1</td></tr><tr><td>Rate of compensation increase</td><td></td><td></td><td></td><td></td></tr><tr><td>(for salary-related plans)</td><td>11.3</td><td>2.0</td><td>-10.4</td><td>-1.8</td></tr><tr><td>Rate of increase in the per capita cost of covered healthcare benefits</td><td>6.0</td><td>1.1</td><td>-5.3</td><td>-0.9</td></tr></table>
<table><tr><td>Balance, December 31, 2003</td><td>$514,177</td></tr><tr><td>Additions during period—depreciation and amortization expense</td><td>82,551</td></tr><tr><td>Deductions during period—disposition and retirements of property</td><td>-1,390</td></tr><tr><td>Balance, December 31, 2004</td><td>595,338</td></tr><tr><td>Additions during period—depreciation and amortization expense</td><td>83,656</td></tr><tr><td>Deductions during period—disposition and retirements of property</td><td>-15,244</td></tr><tr><td>Balance, December 31, 2005</td><td>663,750</td></tr><tr><td>Additions during period—depreciation and amortization expense</td><td>89,564</td></tr><tr><td>Deductions during period—disposition and retirements of property</td><td>-12,807</td></tr><tr><td>Balance, December 31, 2006</td><td>$740,507</td></tr></table>

Question: In which section the sum of Mideast has the highest value?
Answer: Stone