AMERICAN TOWER CORPORATION AND SUBSIDIARIES NOTES TO CONSOLIDATED FINANCIAL STATEMENTS—(Continued) 2003 were $10.08, $7.05, and $6.32 per share, respectively.
Key assumptions used to apply this pricing model are as follows:
## Table 0 ##
Voluntary Option Exchanges—In February 2004, the Company issued to eligible employees 1,032,717 options with an exercise price of $11.19 per share, the fair market value of the Class A common stock on the date of grant.
These options were issued in connection with a voluntary option exchange program entered into by the Company in August 2003, pursuant to which the Company accepted for surrender and cancelled options to purchase a total of 1,831,981 shares of its Class A common stock having an exercise price of $10.25 or greater.
The program, which was offered to both full and part-time employees, excluding the Company’s executive officers and its directors, provided for the grant (at least six months and one day from the surrender date to employees still employed on that date) of new options exercisable for two shares of Class A common stock for every three shares of Class A common stock issuable upon exercise of a surrendered option.
No options were granted to any employees who participated in the exchange offer between the cancellation date and the new grant date.
ATC Mexico Stock Option Plan—The Company maintains a stock option plan in its ATC Mexico subsidiary (ATC Mexico Plan).
The ATC Mexico Plan provides for the issuance of options to officers, employees, directors and consultants of ATC Mexico.
The ATC Mexico Plan limits the number of shares of common stock which may be granted to an aggregate of 360 shares, subject to adjustment based on changes in ATC Mexico’s capital structure.
During 2002, ATC Mexico granted options to purchase 318 shares of ATC Mexico common stock to officers and employees.
Such options were issued at one time with an exercise price of $10,000 per share.
The exercise price per share was at fair market value as determined by the Board of Directors with the assistance of an independent appraisal performed at the Company’s request.
The fair value of ATC Mexico Plan options granted during 2002 were $3,611 per share as determined by using the Black-Scholes option pricing model.
As described in note 11, all outstanding options were exercised in March 2004.
No options under the ATC Mexico Plan were outstanding as of December 31, 2005.
(See note 11. )
ATC South America Stock Option Plan—The Company maintains a stock option plan in its ATC South America subsidiary (ATC South America Plan).
The ATC South America Plan provides for the issuance of options to officers, employees, directors and consultants of ATC South America.
The ATC South America Plan limits the number of shares of common stock which may be granted to an aggregate of 6,144 shares, (an approximate 10.3% interest on a fully-diluted basis), subject to adjustment based on changes in ATC South America’s capital structure.
During 2004, ATC South America granted options to purchase 6,024 shares of ATC South America common stock to officers and employees, including Messrs.  Gearon and Hess, who received options to purchase an approximate 6.7% and 1.6% interest, respectively.
Such options were issued at one time with an exercise price of $1,349 per share.
The exercise price per share was at fair market value on the date of issuance as determined by the Board of Directors with the assistance of an independent appraisal performed at the Company’s request.
The fair value of ATC South America Plan options granted during 2004 were $79 per share as determined by using the Black-Scholes option pricing model.
Options granted vest upon the earlier to occur of (a) the exercise by or on behalf of Mr.  Gearon of his right to sell his interest in ATC South America to the Company, (b) the
HESS CORPORATION AND CONSOLIDATED SUBSIDIARIES NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – (Continued) 7.
Goodwill The changes in the carrying amount of goodwill, all of which relate to the E&P segment, are as follows:
## Table 1 ##
8.
Asset Impairments During 2012, the Corporation recorded total asset impairment charges of $598 million ($360 million after income taxes), including three charges totaling $582 million ($344 million after income taxes) in the E&P segment.
As a result of a competitive bidding process, the Corporation obtained additional information relating to the fair value of its interests in the Cotulla area of the Eagle Ford Shale in Texas in February 2013.
Based on this information and management’s anticipated plan for the assets as of December 31, 2012, the Corporation recorded an impairment charge of $315 million ($192 million after income taxes).
The Corporation also recorded charges of $208 million ($116 million after income taxes) related to increases in estimated abandonment liabilities primarily for non-producing properties which resulted in the book value of the properties exceeding their fair value.
In addition, the Corporation recorded a charge of $59 million ($36 million after income taxes) in the second quarter related to the disposal of certain Eagle Ford properties as part of an asset exchange with its joint venture partner.
In 2012, the Corporation also recorded impairment charges of $16 million relating to certain marketing properties in the M&R segment.
During 2011, the Corporation recorded asset impairment charges of $358 million ($140 million after income taxes) related to increases in the Corporation’s estimated abandonment liabilities primarily for non-producing properties which resulted in the book value of the properties exceeding their fair value.
During 2010, the Corporation recorded an asset impairment charge of $532 million ($334 million after income taxes) to fully impair the carrying value of its 55% interest in the West Mediterranean Block 1 concession (West Med Block), located offshore Egypt, when the Corporation and its partners notified the Egyptian authorities of their decision to cease exploration activities on the block and to relinquish a significant portion of the block.
For both 2011 and 2010, these asset impairments related to the E&P segment.9.
Asset Retirement Obligations The following table describes changes to the Corporation’s asset retirement obligations:
## Table 2 ##
The revisions in 2012 reflect overall increases in estimated abandonment obligations resulting from changes in the expected scope of operations, increases in the time expected to complete dismantlement activities and updates to service rates.
In 2011, the revisions of estimated liabilities reflect an increase in well abandonment obligations resulting from enhanced cement seal verification procedures, changes in scope and timing due to updated work programs and higher service and equipment costs.
## Table 3 ##
(b) Excludes a deferred tax benefit of $674 million which represents the effect of the Denmark hydrocarbon income tax law change to the Chapter 3A regime from the Chapter 3 regime in December 2013.
(c) Asia and Other excludes an income tax charge of $86 million for a disputed application of an international tax treaty.
Oil and Gas Reserves The Corporation’s proved oil and gas reserves are calculated in accordance with the Securities and Exchange Commission (SEC) regulations and the requirements of the Financial Accounting Standards Board.
Proved oil and gas reserves are quantities, which by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible from known reservoirs under existing economic conditions, operating methods and government regulations.
The Corporation’s estimation of net recoverable quantities of liquid hydrocarbons and natural gas is a highly technical process performed by internal teams of geoscience professionals and reservoir engineers.
Estimates of reserves were prepared by the use of appropriate geologic, petroleum engineering, and evaluation principals and techniques that are in accordance with practices generally recognized by the petroleum industry as presented in the publication of the Society of Petroleum Engineers entitled “Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information (Revision as of February 19, 2007).
” The method or combination of methods used in the analysis of each reservoir is based on the maturity of the reservoir, the completeness of the subsurface data available at the time of the estimate, the stage of reservoir development and the production history.
Where applicable, reliable technologies may be used in reserve estimation, as defined in the SEC regulations.
These technologies, including computational methods, must have been field tested and demonstrated to provide reasonably certain results with consistency and repeatability in the formation being evaluated or in an analogous formation.
In order for reserves to be classified as proved, any required government approvals must be obtained and depending on the cost of the project, either senior management or the Board of Directors must commit to fund the development.
The Corporation’s proved reserves are subject to certain risks and uncertainties, which are discussed in Item 1A, Risk Factors Related to Our Business and Operations of this Form 10-K.  Internal Controls The Corporation maintains internal controls over its oil and gas reserve estimation process which are administered by the Corporation’s Vice President of E&P Technology and its Chief Financial Officer.
Estimates of reserves are prepared by technical staff that work directly with the oil and gas properties using standard reserve estimation guidelines, definitions and methodologies.
Each year, reserve estimates for a selection of the Corporation’s assets are subject to internal technical audits and reviews.
In addition, an independent third party reserve engineer reviews and audits a significant portion of the Corporation’s reported reserves (see pages 90 through 91).
Reserve estimates are reviewed by senior management and the Board of directors.
Qualifications The person primarily responsible for overseeing the preparation of the Corporation’s oil and gas reserves during 2013 was Mr.  Randy Johnson, Vice President of E&P Technology.
Mr.  Johnson is a member of the Society of Petroleum Engineers and has over 30 years of experience in the oil and gas industry with a BS degree in Engineering and a MS degree in Petroleum Engineering.
He is a licensed professional engineer in Texas.
His experience includes over 20 years primarily focused on oil and gas subsurface understanding and reserves estimation in both domestic and international areas.
The Corporation’s upstream technology organization, which Mr.  Johnson manages, focuses on oil and gas industry subsurface and reservoir engineering technologies and evaluation techniques.
Mr.  Johnson is also responsible for the Corporation’s Global Reserves group, which is the internal organization responsible for establishing the policies and processes used within the operating units to estimate reserves and perform internal technical reserve audits and reviews.

<table><tr><td></td><td>July 1, 2005 – December 31, 2005</td><td>January 1, 2005 – June 30, 2005</td><td>2004</td><td>2003</td></tr><tr><td>Approximate risk-free interest rate</td><td>3.22% - 4.40%</td><td>4.17% - 4.40%</td><td>4.23%</td><td>4.00%</td></tr><tr><td>Expected life of option grants</td><td>6.25 years</td><td>4 years</td><td>4 years</td><td>4 years</td></tr><tr><td>Expected volatility of underlying stock</td><td>29.6%</td><td>75.3% - 79.2%</td><td>80.6%</td><td>86.6%</td></tr><tr><td>Expected volatility of underlying stock (ATC Mexico and ATC South America Plans)</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr><tr><td>Expected dividends</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td></tr></table>
<table><tr><td></td><td>2012</td><td>2011</td></tr><tr><td></td><td colspan="2">(In millions)</td></tr><tr><td>Beginning balance at January 1</td><td>$2,305</td><td>$2,408</td></tr><tr><td>Dispositions</td><td>-97</td><td>-103</td></tr><tr><td>Ending balance at December 31</td><td>$2,208</td><td>$2,305</td></tr></table>
<table><tr><td></td><td>2012</td><td>2011</td></tr><tr><td></td><td colspan="2">(In millions)</td></tr><tr><td>Asset retirement obligations at January 1</td><td>$2,071</td><td>$1,358</td></tr><tr><td>Liabilities incurred</td><td>186</td><td>25</td></tr><tr><td>Liabilities settled or disposed of</td><td>-324</td><td>-334</td></tr><tr><td>Accretion expense</td><td>135</td><td>96</td></tr><tr><td>Revisions of estimated liabilities</td><td>529</td><td>947</td></tr><tr><td>Foreign currency translation</td><td>64</td><td>-21</td></tr><tr><td>Asset retirement obligations at December 31</td><td>2,661</td><td>2,071</td></tr><tr><td>Less: Current obligations</td><td>449</td><td>227</td></tr><tr><td>Long-term obligations at December 31</td><td>$2,212</td><td>$1,844</td></tr></table>
<table><tr><td></td><td> <i>2013</i></td><td>2012</td><td> <i>2011</i></td><td></td></tr><tr><td></td><td colspan="3"> <i>(In millions)</i></td><td></td></tr><tr><td><i>Sales and other operating revenues</i></td><td>$860</td><td>$518</td><td>$996</td><td><i></i></td></tr><tr><td><i>Costs and expenses</i></td><td></td><td></td><td></td><td></td></tr><tr><td><i>Operating costs and expenses</i></td><td>376</td><td>297</td><td>271</td><td><i></i></td></tr><tr><td><i>Production and severance taxes</i></td><td>6</td><td>5</td><td>19</td><td><i></i></td></tr><tr><td><i>Exploration expenses, including dry holes and lease impairment</i></td><td>6</td><td>—</td><td>10</td><td><i></i></td></tr><tr><td><i>General, administrative and other expenses</i></td><td>8</td><td>10</td><td>9</td><td><i></i></td></tr><tr><td><i>Depreciation, depletion and amortization</i></td><td>364</td><td>139</td><td>232</td><td><i></i></td></tr><tr><td><i>Total costs and expenses</i></td><td>760</td><td>451</td><td>541</td><td><i></i></td></tr><tr><td><i>Results of operations before income taxes</i></td><td>100</td><td>67</td><td>455</td><td><i></i></td></tr><tr><td><i>Provision(benefit) for income taxes</i></td><td>36</td><td>-82</td><td>295</td><td><i></i></td></tr><tr><td><i>Results of operations</i></td><td>$64</td><td>$149</td><td>$160</td><td><i></i></td></tr></table>

Question: Which year is the Sales and other operating revenues the least?
Answer: 2012