ITEM 2.
PROPERTIES Our principal offices are located in Boston, Southborough and Woburn, Massachusetts; Atlanta, Georgia; Cary, North Carolina; Mexico City, Mexico; and Sao Paulo, Brazil.
Details of each of these offices are provided below:
## Table 0 ##
(1) The facility in Woburn contains a total of 163,000 square feet of space.
Approximately 57,100 square feet of space is occupied by our lease administration office and our broadcast division, and we lease the remaining space to unaffiliated tenants.
In addition to the principal offices set forth above, we maintain 15 regional area offices in the United States through which we operate our tower leasing and services businesses.
We believe that our owned and leased facilities are suitable and adequate to meet our anticipated needs.
We have also established an office in Delhi, India to pursue business opportunities in India and Southeast Asia, and we have an international business development group based in London, England.
Our interests in our communications sites are comprised of a variety of ownership interests, including leases created by long-term ground lease agreements, easements, licenses or rights-of-way granted by government entities.
Pursuant to the loan agreement for the Securitization, the tower sites subject to the Securitization are subject to mortgages, deeds of trust and deeds to secure the loan.
A typical tower site consists of a compound enclosing the tower site, a tower structure, and one or more equipment shelters that house a variety of transmitting, receiving and switching equipment.
There are three principal types of towers: guyed, selfsupporting lattice, and monopole.  ?
A guyed tower includes a series of cables attaching separate levels of the tower to anchor foundations in the ground.
A guyed tower can reach heights of up to 2,000 feet.
A guyed tower site for a typical broadcast tower can consist of a tract of land of up to 20 acres.  ?
A lattice tower typically tapers from the bottom up and usually has three or four legs.
A lattice tower can reach heights of up to 1,000 feet.
Depending on the height of the tower, a lattice tower site for a wireless communications tower can consist of a tract of land of 10,000 square feet for a rural site or less than 2,500 square feet for a metropolitan site.  ?
A monopole is a tubular structure that is used primarily to address space constraints or aesthetic concerns.
Monopoles typically have heights ranging from 50 to 200 feet.
A monopole tower site of the kind typically used in metropolitan areas for a wireless communications tower can consist of a tract of land of less than 2,500 square feet.
ITEM 6.
SELECTED FINANCIAL DATA You should read the selected financial data in conjunction with our “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” and our audited consolidated financial statements and the related notes to those consolidated financial statements included in this Annual Report.
Our continuing operations are reported in two segments: rental and management and network development services.
In accordance with generally accepted accounting principles, the consolidated statements of operations for all periods presented in this “Selected Financial Data” have been adjusted to reflect certain businesses as discontinued operations (see note 1 to our consolidated financial statements included in this Annual Report).
Year-to-year comparisons are significantly affected by our acquisitions, dispositions and, to a lesser extent, construction of towers.
Our August 2005 merger with SpectraSite, Inc.  (as discussed in note 4 to our consolidated financial statements included in this Annual Report) significantly impacts the comparability of reported results between periods.
## Table 1 ##
Other Operating Data: Ratio of earnings to fixed charges(2) . . . . . . . . . . . . . . . . . .  1.50x 1.25x — — —
AMERICAN TOWER CORPORATION AND SUBSIDIARIES NOTES TO CONSOLIDATED FINANCIAL STATEMENTS—(Continued) accounting and reporting requirements for conditional obligations associated with the Company’s legal obligation to retire tangible long-lived assets and the related asset retirement costs.
The fair value of a liability for asset retirement obligations is recognized in the period in which it is incurred and can be reasonably estimated.
Such asset retirement costs are capitalized as part of the carrying amount of the related long-lived asset and depreciated over the asset’s estimated useful life.
Fair value estimates of liabilities for asset retirement obligations generally involve discounting of estimated future cash flows.
Periodic accretion of such liabilities due to the passage of time is recorded as an operating expense.
The Company has certain legal obligations related to tower assets which fall within the scope of SFAS No.143 and FIN No.47, principally obligations to remediate leased land on which certain of the Company’s tower assets are located.
The significant assumptions used in estimating the Company’s aggregate asset retirement obligation are: timing of tower removals; cost of tower removals; timing and number of land lease renewals; expected inflation rates; and creditadjusted risk-free interest rates that approximate the Company’s incremental borrowing rate.
The adoption of FIN No.47 primarily resulted in the acceleration of settlement date assumptions, as FIN No.47 precludes the Company from considering non-contractual lease renewal periods in determining its settlement date assumptions.
The Company adopted the provisions of SFAS No.143 as of January 1, 2003 and the provisions of FIN No.47 as of December 31, 2005.
Upon adoption of the provisions of FIN No.47, the Company recognized a $35.5 million charge (net of an $11.7 million tax benefit) as a cumulative effect of a change in accounting principle in the consolidated statement of operations for the year ended December 31, 2005.
In addition, the adoption of FIN No.47 resulted in an increase to the tower assets included in property and equipment, net of $66.9 million and an increase in the asset retirement obligation of $114.0 million.
The Company’s asset retirement obligation is included in other long-term liabilities in the accompanying consolidated balance sheets.
The changes in the carrying value of the Company’s asset retirement obligations for years ended December 31, 2007, 2006 and 2005 are as follows (in thousands):
## Table 2 ##
Fair Value of Financial Instruments—The carrying values of the Company’s financial instruments, with the exception of long-term obligations, including current portion, reasonably approximate the related fair values as of December 31, 2007 and 2006.
As of December 31, 2007, the carrying amount and fair value of long-term obligations, including current portion, were $4.3 billion and $4.6 billion, respectively.
As of December 31, 2006, the carrying amount and fair value of long-term obligations, including current portion, were $3.5 billion and $4.1 billion, respectively.
Fair values are based primarily on quoted market prices for those or similar instruments.
Retirement Plan—The Company has a 401(k) plan covering substantially all employees who meet certain age and employment requirements.
The Company’s matching contribution is 50% up to a maximum 6% of a participant’s contributions.
The Company contributed approximately $1.5 million, $1.5 million and $1.1 million to the plan for the years ended December 31, 2007, 2006 and 2005, respectively.

<table><tr><td>Location</td><td>Function</td><td>Size (square feet)</td><td>Property Interest</td></tr><tr><td>Boston, MA</td><td>Corporate Headquarters, US Tower Division Headquarters and American Tower International Headquarters</td><td>19,600</td><td>Leased</td></tr><tr><td>Southborough, MA</td><td>Information Technology Data Center</td><td>13,900</td><td>Leased</td></tr><tr><td>Woburn, MA</td><td>US Tower Division, Lease Administration, Site Leasing Management and Broadcast Division Headquarters</td><td>57,800</td><td>Owned-1</td></tr><tr><td>Atlanta, GA</td><td>US Tower Division, Accounting Services Headquarters</td><td>21,400</td><td>Leased</td></tr><tr><td>Cary, North Carolina</td><td>US Tower Division, New Site Development, Site Operations and Structural Engineering Services Headquarters</td><td>17,500</td><td>Leased</td></tr><tr><td>Mexico City, Mexico</td><td>Mexico Headquarters</td><td>11,000</td><td>Leased</td></tr><tr><td>Sao Paulo, Brazil</td><td>Brazil Headquarters</td><td>5,200</td><td>Leased</td></tr></table>
<table><tr><td></td><td colspan="5">Year Ended December 31,</td></tr><tr><td></td><td>2007</td><td>2006</td><td>2005</td><td>2004</td><td>2003</td></tr><tr><td></td><td colspan="5">(In thousands, except per share data)</td></tr><tr><td> Statements of Operations Data:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Revenues:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Rental and management</td><td>$1,425,975</td><td>$1,294,068</td><td>$929,762</td><td>$684,422</td><td>$619,697</td></tr><tr><td>Network development services</td><td>30,619</td><td>23,317</td><td>15,024</td><td>22,238</td><td>12,796</td></tr><tr><td>Total operating revenues</td><td>1,456,594</td><td>1,317,385</td><td>944,786</td><td>706,660</td><td>632,493</td></tr><tr><td>Operating expenses:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Costs of operations (exclusive of items shown separately below)</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Rental and management</td><td>343,450</td><td>332,246</td><td>247,781</td><td>195,242</td><td>192,380</td></tr><tr><td>Network development services</td><td>16,172</td><td>11,291</td><td>8,346</td><td>16,220</td><td>7,419</td></tr><tr><td>Depreciation, amortization and accretion</td><td>522,928</td><td>528,051</td><td>411,254</td><td>329,449</td><td>330,414</td></tr><tr><td>Selling, general, administrative and development expense</td><td>186,483</td><td>159,324</td><td>108,059</td><td>83,094</td><td>83,492</td></tr><tr><td>Impairments, net loss on sale of long-lived assets, restructuring and merger related expense</td><td>9,198</td><td>2,572</td><td>34,232</td><td>23,876</td><td>31,656</td></tr><tr><td>Total operating expenses</td><td>1,078,231</td><td>1,033,484</td><td>809,672</td><td>647,881</td><td>645,361</td></tr><tr><td>Operating income (loss)</td><td>378,363</td><td>283,901</td><td>135,114</td><td>58,779</td><td>-12,868</td></tr><tr><td>Interest income, TV Azteca, net</td><td>14,207</td><td>14,208</td><td>14,232</td><td>14,316</td><td>14,222</td></tr><tr><td>Interest income</td><td>10,848</td><td>9,002</td><td>4,402</td><td>4,844</td><td>5,255</td></tr><tr><td>Interest expense</td><td>-235,824</td><td>-215,643</td><td>-222,419</td><td>-262,237</td><td>-279,783</td></tr><tr><td>Loss on retirement of long-term obligations</td><td>-35,429</td><td>-27,223</td><td>-67,110</td><td>-138,016</td><td>-46,197</td></tr><tr><td>Other income (expense)</td><td>20,675</td><td>6,619</td><td>227</td><td>-2,798</td><td>-8,598</td></tr><tr><td>Income (loss) before income taxes, minority interest and income (loss) on equity method investments</td><td>152,840</td><td>70,864</td><td>-135,554</td><td>-325,112</td><td>-327,969</td></tr><tr><td>Income tax (provision) benefit</td><td>-59,809</td><td>-41,768</td><td>-5,714</td><td>83,338</td><td>85,567</td></tr><tr><td>Minority interest in net earnings of subsidiaries</td><td>-338</td><td>-784</td><td>-575</td><td>-2,366</td><td>-3,703</td></tr><tr><td>Income (loss) on equity method investments</td><td>19</td><td>26</td><td>-2,078</td><td>-2,915</td><td>-21,221</td></tr><tr><td>Income (loss) from continuing operations before cumulative effect of change in accounting principle</td><td>$92,712</td><td>$28,338</td><td>$-143,921</td><td>$-247,055</td><td>$-267,326</td></tr><tr><td>Basic and diluted income (loss) per common share from continuing operations before cumulative effect of change in accountingprinciple(1)</td><td>$0.22</td><td>$0.06</td><td>$-0.47</td><td>$-1.10</td><td>$-1.28</td></tr><tr><td>Weighted average common shares outstanding-1</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Basic</td><td>413,167</td><td>424,525</td><td>302,510</td><td>224,336</td><td>208,098</td></tr><tr><td>Diluted</td><td>426,079</td><td>436,217</td><td>302,510</td><td>224,336</td><td>208,098</td></tr><tr><td> Other Operating Data:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Ratio of earnings to fixed charges-2</td><td>1.50x</td><td>1.25x</td><td>—</td><td>—</td><td>—</td></tr></table>
<table><tr><td></td><td>2007</td><td>2006</td><td> 2005</td></tr><tr><td>Beginning balance as of January 1,</td><td>$174,980</td><td>$164,222</td><td>$23,464</td></tr><tr><td>(Deductions), additions and revisions in estimated cash flows, net of settlements</td><td>-3,776</td><td>-710</td><td>2,587</td></tr><tr><td>Accretion expense</td><td>12,958</td><td>11,468</td><td>3,069</td></tr><tr><td>Liability assumed in merger with SpectraSite, Inc.</td><td></td><td></td><td>21,126</td></tr><tr><td>Increase due to change in accounting principle</td><td></td><td></td><td>113,976</td></tr><tr><td>Balance as of December 31,</td><td>$184,162</td><td>$174,980</td><td>$164,222</td></tr></table>

Question: what portion of the woburn property owned by the american tower corporation is subleased?
Answer: 2e-05