AMERICAN TOWER CORPORATION AND SUBSIDIARIES NOTES TO CONSOLIDATED FINANCIAL STATEMENTS—(Continued) 6.
LONG-TERM OBLIGATIONS Outstanding amounts under the Company’s long-term financing arrangements consist of the following as of December 31, (in thousands):
## Table 0 ##
Commercial Mortgage Pass-Through Certificates, Series 2007-1—During the year ended December 31, 2007, the Company completed a securitization transaction (the Securitization) involving assets related to 5,295 broadcast and wireless communications towers (the Secured Towers) owned by two special purpose subsidiaries of the Company, through a private offering of $1.75 billion of Commercial Mortgage Pass-Through Certificates, Series 2007-1 (the Certificates).
The Certificates were issued by American Tower Trust I (the Trust), a trust established by American Tower Depositor Sub, LLC (the Depositor), an indirect wholly owned special purpose subsidiary of the Company.
The assets of the Trust consist of a recourse loan (the Loan) initially made by the Depositor to American Tower Asset Sub, LLC and American Tower Asset Sub II, LLC (the Borrowers), pursuant to a Loan and Security Agreement among the foregoing parties dated as of May 4, 2007 (the Loan Agreement).
The Borrowers are special purpose entities formed solely for the purpose of holding the Secured Towers subject to the Securitization.
The Certificates were issued in seven separate classes, comprised of Class A-FX, Class A-FL, Class B, Class C, Class D, Class E and Class F.  Each of the Certificates in Classes B, C, D, E and F are subordinated in right of payment to any other class of Certificates which has an earlier alphabetical designation.
The Certificates were issued with terms identical to the Loan except for the Class A-FL Certificates, which bear interest at a floating rate while the related component of the Loan bears interest at a fixed rate, as described below.
The various classes of Certificates were issued with a weighted average interest rate of approximately 5.61%.
The Certificates have an expected life of approximately seven years with a final repayment date in April 2037.
The Company used the net proceeds from the Securitization to repay all amounts outstanding under the SpectraSite credit facilities, including approximately $765.0 million in principal, plus accrued interest thereon and other costs and expenses related thereto, as well as to repay approximately $250.0 million drawn under the revolving loan component of the credit facilities at the American Tower operating company level.
An additional $349.5 million of the proceeds was used to fund the Company’s tender offer and consent solicitation for the ATI
December 31, 2015, as compared to $304 million as of December 31, 2014.
These tax attributes will expire periodically beginning in 2016.
The current accounting standard for stock-based compensation prohibits the recognition of windfall tax benefits from stock-based compensation deducted for tax return purposes until realized through a reduction of income taxes payable.
We have $32 million and $2 million of U. S.  tax net operating loss as of December 31, 2015 and December 31, 2014 respectively, which will be recog- nized through additional paid in capital upon realization of the tax benefit through reduction of income tax payable.
These amounts were not included in the gross deferred taxes as of December 31, 2015 and December 31, 2014.
After consideration of all positive and negative evidence, we believe that it is more likely than not that a portion of the deferred tax assets will not be realized.
As a result, we established a valuation allowance of $499 million as of December 31, 2015 and $450 million as of December 31, 2014, representing an increase of $49 million.
The increase in the valuation allowance as of December 31, 2015, as compared to December 31, 2014, is attributable primarily to increases in certain deferred tax assets that are not more likely than not realizable.
The income tax impact of the unrealized gain or loss component of other comprehensive income and stockholders’ equity was a charge of $25 million in 2015, a charge of $21 million in 2014, and a charge of $76 million in 2013.
We have not provided U. S.  income taxes and foreign withholding taxes on the undistributed earnings of foreign subsidiaries as of December 31, 2015 because we intend to permanently reinvest such earnings outside the U. S.  As of December 31, 2015, the cumulative amount of excess financial reporting basis over the tax basis of investments in foreign subsidiaries that is indefinitely reinvested is approximately $8.9 billion.
Generally, such amounts become subject to U. S.  taxation upon the remittance of dividends and under certain other circumstances.
It is not practicable to estimate the amount of deferred tax liability related to investments in these foreign subsidiaries.
We obtain tax incentives through Free Trade Zone Regime offered in Costa Rica which allows 100% exemption from income tax in the first eight years of operations and 50% exemption in the following four years.
This tax incentive resulted in income tax savings of $7 million for 2015, $7 million for 2014, and $6 million for 2013.
The tax incentive for 100% exemption from income tax is expected to expire in 2023.
The impact of per share earnings is immaterial for 2015, 2014 and 2013.
As of December 31, 2015, we had $1.056 billion of gross unrecog- nized tax benefits, of which a net $900 million, if recognized, would affect our effective tax rate.
As of December 31, 2014, we had $1.047 billion of gross unrecognized tax benefits, of which a net $903 million, if recognized, would affect our effective tax rate.
As of December 31, 2013, we had $1.102 billion of gross unrecognized tax benefits, of which a net $941 million, if recog- nized, would affect our effective tax rate.
A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in millions):
## Table 1 ##
We are subject to U. S.  Federal income tax as well as income tax of multiple state and foreign jurisdictions.
We have concluded all U. S.  federal income tax matters through 2000, all foreign income tax matters through 2002 and substantially all material state and local income tax matters through 2005.
We have received Notices of Deficiency from the Internal Revenue Service (IRS) reflecting proposed audit adjustments for Guidant Corporation for its 2001 through 2006 tax years and Boston Scientific Corporation for its 2006 and 2007 tax years.
The total incremental tax liability asserted by the IRS for the applicable periods is $1.162 billion plus interest.
The primary issue in dispute for all years is the transfer pricing associated with the technology license agreements between domestic and foreign subsidiaries of Guidant.
In addition, the IRS has proposed adjustments in connection with the financial terms of our Transaction Agreement with Abbott Laboratories pertaining to the sale of Guidant’s vas- cular intervention business to Abbott in April 2006.
In addition to the Notices of Deficiency, during 2014, we received a Revenue Agent Report from the IRS reflecting significant proposed audit adjustments to our 2008, 2009, and 2010 tax years based upon the same transfer pricing methodologies that the IRS applied to our 2001 through 2007 tax years.
We do not agree with the transfer pricing methodologies applied by the IRS or its resulting assessment.
In addition, we believe that the IRS positions with regard to these matters are inconsistent with the applicable tax laws and the existing Treasury
The aggregate carrying amount of our cost method investments was $45 million as of December 31, 2015 and $27 million as of December 31, 2014.
In addition, we had notes receivable from certain companies that we account for under the cost method of $30 million as of December 31, 2015 and $17 million as of December 31, 2014.
As of December 31, 2015, the book value of our equity method investments exceeded our share of the book value of the investees’ underlying net assets by approximately $80 million, which represents amortizable intangible assets and in-process research and development, corresponding deferred tax liabilities, and goodwill.
During the year ended December 31, 2015, the net losses from our equity method adjustments, presented within the Other, net caption of our condensed consolidated statement of operations were immaterial.
We did not close any material strategic investments in the twelve months ended December 31, 2014.
NOTE C—DIVESTITURES In January 2011, we closed the sale of our Neurovascular business to Stryker Corporation for a purchase price of $1.500 billion in cash.
We received $1.450 billion during 2011, an additional $10 million during 2012, $30 million during 2013 and we received the final amount due to us in 2014.
At the time of divestiture, due to our continuing involvement in the operations of the Neurovascular business following the transaction, the divestiture did not meet the criteria for presentation as a discontinued operation.
Our sales related to our divested Neurovascular business have declined as the various transition services and supply agreements have terminated.
We recorded a gain of $12 million during 2014 and a gain of $38 million during 2013 associated with the transaction.
We recorded revenue related to the Neurovascular business following its divestiture of $4 million in 2014 and $58 million in 2013.
NOTE D—GOODWILL AND OTHER INTANGIBLE ASSETS The gross carrying amount of goodwill and other intangible assets and the related accumulated amortization for intangible assets subject to amortization and accumulated write-offs of goodwill as of December 31, 2015 and 2014 is as follows:
## Table 2 ##
During 2015, we reclassified approximately $77 million of core technology not previously subject to amortization to amortizable intangible assets due to projected changes in the market for this technology.
We tested the intangible asset for impairment prior to this reclassification and determined that the asset was not impaired.
In addition, during 2015, we reclassified a total of $77 million of IPR&D assets not previously subject to amortization to amortizable intangible assets.
The reclassification of IPR&D to amortizable intangible assets was primarily related to the receipt of FDA approval of the WATCHMAN?
device.
Our technology-related intangible assets that are not subject to amortization represent technical processes, intellectual property and/or institutional understanding acquired through business combinations that are fundamental to the on-going operations of our business and have no limit to their useful life.
Our technologyrelated intangible assets that are not subject to amortization are comprised primarily of certain acquired balloon and other technology, which is foundational to our continuing operations within the Cardiovascular market and other markets within interventional medicine.
We assess our indefinite-lived intangible assets at least annually for impairment and reassess their classi- fication as indefinite-lived assets.
We assess qualitative factors to determine whether the existence of events and circumstances indicate that it is more likely than not that our indefinite-lived
ITEM 6.
SELECTED FINANCIAL DATA We derived the consolidated statement of income and other financial data for the years ended December 31, 2015, 2014 and 2013 and the selected consolidated balance sheet data as of December 31, 2015 and 2014 from the audited consolidated financial statements included elsewhere in this report.
We derived the selected historical financial data for the years ended December 31, 2012 and 2011 and the selected consolidated balance sheets as of December 31, 2013, 2012 and 2011 from our audited consolidated financial statements that are not included in this report.
The selected consolidated financial data set forth below should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our audited consolidated financial statements and notes thereto included elsewhere in this report.
Our historical results are not necessarily indicative of the results to be expected in any future period.
## Table 3 ##
General and administrative.
General and administrative expense increased from $206.0 million in 2014 to $297.7 million in 2015, an increase of $91.8 million, or 44.5%.
The increase was primarily due to the impact of our acquisition of Comdata completed in the fourth quarter of 2014 and incremental stock based compensation of $52.5 million, partially offset by decreases due to changes in foreign exchange rates.
Depreciation and amortization.
Depreciation and amortization increased from $112.4 million in 2014 to $193.5 million in 2015, an increase of $81.1 million, or 72.2%.
The increase was primarily due to our acquisition of Comdata completed during the fourth quarter of 2014, which resulted in an increase of $91.3 million related to the amortization of acquired intangible assets for customer and vendor relationships, trade names and trademarks, non-compete agreements and software, as well as depreciation of acquired fixed assets, partially offset by decreases due to changes in foreign exchange rates.
Other operating, net.
Other operating, net decreased from a $29.5 million favorable impact in 2014 to a $4.2 million favorable impact in 2015, a decrease of $25.3 million, or 85.8%.
In 2015, the balance relates primarily to the net favorable impact of the additional reversals of various contingent liabilities for tax indemnifications related to our acquisitions of DB and VB in Brazil.
Included in other operating, net in 2014 is $28.1 million of favorable impact related to fair value adjustments recorded for contingent consideration arrangements for our acquisition of VB in Brazil and $1.4 million from the reversal of other various contingent liabilities for tax indemnifications related to our acquisitions of DB and VB in Brazil.
Equity method investment loss On April 28, 2014, we acquired a minority interest in Masternaut, a provider of telematics solutions to commercial fleets in Europe, which we account for as an equity method investment.
The increase in equity method investment loss from $8.6 million in 2014 to $57.7 million in 2015 was primarily due to a non-cash impairment charge of $40 million recorded in the fourth quarter of 2015.
We regularly evaluate our investments, which are not carried at fair value, for other than temporary impairment in accordance with U.  S.  GAAP.
During the fourth quarter, we determined that the performance improvement initiatives at Masternaut will take longer to implement than we originally projected.
As a result, we have recorded a $40 million non-cash impairment charge in our equity method investment.
Interest expense, net Interest expense increased from $28.9 million in 2014 to $71.3 million in 2015, an increase of $42.5 million, or 147.2%.
The increase is due to an increase in borrowings in 2015 over 2014, primarily due to funding of the purchase price for our acquisition of Comdata.

<table><tr><td></td><td>2008</td><td>2007</td></tr><tr><td>Commercial Mortgage Pass-Through Certificates, Series 2007-1</td><td>$1,750,000</td><td>$1,750,000</td></tr><tr><td>Revolving credit facility</td><td>750,000</td><td>825,000</td></tr><tr><td>Term loan</td><td>325,000</td><td>—</td></tr><tr><td>7.25% senior subordinated notes</td><td>288</td><td>288</td></tr><tr><td>7.50% senior notes</td><td>225,000</td><td>225,000</td></tr><tr><td>7.125% senior notes</td><td>501,107</td><td>502,202</td></tr><tr><td>7.00% senior notes</td><td>500,000</td><td>500,000</td></tr><tr><td>5.0% convertible notes</td><td>59,683</td><td>59,683</td></tr><tr><td>3.25% convertible notes</td><td>—</td><td>18,333</td></tr><tr><td>3.00% convertible notes</td><td>161,893</td><td>344,568</td></tr><tr><td>Other convertible notes</td><td>41</td><td>41</td></tr><tr><td>Notes payable and capital leases</td><td>60,134</td><td>60,169</td></tr><tr><td>Total</td><td>4,333,146</td><td>4,285,284</td></tr><tr><td>Less current portion of long-term obligations</td><td>-1,837</td><td>-1,817</td></tr><tr><td>Long-term obligations</td><td>$4,331,309</td><td>$4,283,467</td></tr></table>
<table><tr><td></td><td colspan="3">Year Ended December 31,</td></tr><tr><td></td><td>2015</td><td>2014</td><td>2013</td></tr><tr><td>Beginning Balance</td><td>$1,047</td><td>$1,102</td><td>$1,088</td></tr><tr><td>Additions based on positions related to the current year</td><td>32</td><td>44</td><td>59</td></tr><tr><td>Additions based on positions related to prior years</td><td>38</td><td>3</td><td>43</td></tr><tr><td>Reductions for tax positions of prior years</td><td>-36</td><td>-87</td><td>-42</td></tr><tr><td>Settlements with taxing authorities</td><td>-18</td><td>-5</td><td>-15</td></tr><tr><td>Statute of limitation expirations</td><td>-7</td><td>-10</td><td>-31</td></tr><tr><td>Ending Balance</td><td>$1,056</td><td>$1,047</td><td>$1,102</td></tr></table>
<table><tr><td></td><td colspan="2">As of December 31, 2015</td><td colspan="2">As of December 31, 2014</td></tr><tr><td>(in millions)</td><td>Gross Carrying Amount</td><td>AccumulatedAmortization/ Write-offs</td><td>Gross Carrying Amount</td><td>AccumulatedAmortization/ Write-offs</td></tr><tr><td>Amortizable intangible assets</td><td></td><td></td><td></td><td></td></tr><tr><td>Technology-related</td><td>$8,948</td><td>$-4,054</td><td>$8,406</td><td>$-3,697</td></tr><tr><td>Patents</td><td>520</td><td>-358</td><td>519</td><td>-342</td></tr><tr><td>Other intangible assets</td><td>1,529</td><td>-610</td><td>875</td><td>-533</td></tr><tr><td></td><td>$10,997</td><td>$-5,022</td><td>$9,800</td><td>$-4,572</td></tr><tr><td>Unamortizable intangible assets</td><td></td><td></td><td></td><td></td></tr><tr><td>Goodwill</td><td>$16,373</td><td>$-9,900</td><td>$15,798</td><td>$-9,900</td></tr><tr><td>In-process research and development (IPR&D)</td><td>99</td><td></td><td>181</td><td></td></tr><tr><td>Technology-related</td><td>120</td><td>—</td><td>197</td><td>—</td></tr><tr><td></td><td>$16,592</td><td>$-9,900</td><td>$16,176</td><td>$-9,900</td></tr></table>
<table><tr><td> (in thousands, except per share data)</td><td>2015</td><td>2014</td><td> 2013</td><td> 2012</td><td>2011</td></tr><tr><td> Consolidated statement of income data:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Revenues, net</td><td>$1,702,865</td><td>$1,199,390</td><td>$895,171</td><td>$707,534</td><td>$519,591</td></tr><tr><td>Expenses:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Merchant commissions</td><td>108,257</td><td>96,254</td><td>68,143</td><td>58,573</td><td>51,199</td></tr><tr><td>Processing</td><td>331,073</td><td>173,337</td><td>134,030</td><td>115,446</td><td>84,516</td></tr><tr><td>Selling</td><td>109,075</td><td>75,527</td><td>57,346</td><td>46,429</td><td>36,606</td></tr><tr><td>General and administrative</td><td>297,715</td><td>205,963</td><td>142,283</td><td>110,122</td><td>84,765</td></tr><tr><td>Depreciation and amortization</td><td>193,453</td><td>112,361</td><td>72,737</td><td>52,036</td><td>36,171</td></tr><tr><td>Other operating, net</td><td>-4,242</td><td>-29,501</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Operating income</td><td>667,534</td><td>565,449</td><td>420,632</td><td>324,928</td><td>226,334</td></tr><tr><td>Equity method investment loss</td><td>57,668</td><td>8,586</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Other expense (income), net</td><td>2,523</td><td>-700</td><td>602</td><td>1,121</td><td>-589</td></tr><tr><td>Interest expense, net</td><td>71,339</td><td>28,856</td><td>16,461</td><td>13,017</td><td>13,377</td></tr><tr><td>Loss on early extinguishment of debt</td><td>—</td><td>15,764</td><td>—</td><td>—</td><td>2,669</td></tr><tr><td>Total other expense</td><td>131,530</td><td>52,506</td><td>17,063</td><td>14,138</td><td>15,457</td></tr><tr><td>Income before income taxes</td><td>536,004</td><td>512,943</td><td>403,569</td><td>310,790</td><td>210,877</td></tr><tr><td>Provision for income taxes</td><td>173,573</td><td>144,236</td><td>119,068</td><td>94,591</td><td>63,542</td></tr><tr><td>Net income</td><td>$362,431</td><td>$368,707</td><td>$284,501</td><td>$216,199</td><td>$147,335</td></tr><tr><td>Earnings per share:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Earnings per share, basic</td><td>$3.94</td><td>$4.37</td><td>$3.48</td><td>$2.59</td><td>$1.83</td></tr><tr><td>Earnings per share, diluted</td><td>$3.85</td><td>$4.24</td><td>$3.36</td><td>$2.52</td><td>$1.76</td></tr><tr><td>Weighted average shares outstanding, basic</td><td>92,023</td><td>84,317</td><td>81,793</td><td>83,328</td><td>80,610</td></tr><tr><td>Weighted average shares outstanding, diluted</td><td>94,139</td><td>86,982</td><td>84,655</td><td>85,736</td><td>83,654</td></tr><tr><td></td><td colspan="5">As of December 31,</td></tr><tr><td> (in thousands)</td><td>2015</td><td>2014</td><td> 2013</td><td> 2012</td><td>2011</td></tr><tr><td> Consolidated balance sheet data:</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td> Cash and cash equivalents </td><td>$447,152</td><td>$477,069</td><td>$338,105</td><td>$283,649</td><td>$285,159</td></tr><tr><td>Restricted cash-1</td><td>167,492</td><td>135,144</td><td>48,244</td><td>53,674</td><td>55,762</td></tr><tr><td>Total assets-2</td><td>7,891,868</td><td>8,524,701</td><td>3,908,717</td><td>2,721,870</td><td>2,349,169</td></tr><tr><td>Total debt</td><td>2,937,062</td><td>3,593,717</td><td>1,486,378</td><td>925,092</td><td>704,265</td></tr><tr><td>Total stockholders’ equity-2</td><td>2,830,047</td><td>2,618,562</td><td>1,223,502</td><td>913,822</td><td>811,436</td></tr></table>

Question: What's the average of Patents Gross Carrying Amount in 2015? (in millions)
Answer: 520