2002.
The amount of the Company's NOLs incurred prior to each ownership change is limited based on the value of the Company on the respective dates of ownership change.
Future ownership changes, if any, could give rise to further limitation under IRC Section 382.
At December 31, 2013, after considering the impact of IRC Section 382, the Company had approximately $1.4 billion of available NOL's for U. S.  federal income tax purposes, comprised of $0.3 billion of NOLs generated from operating losses and approximately $1.1 billion of NOLs generated from equity-related transactions, including equity-based compensation and stock warrants.
The NOLs mainly expire from December 31, 2019 to December 31, 2021.
The utilization of these NOLs is dependent upon the Company's ability to generate sufficient future taxable income in the United States.
The Company periodically evaluates the likelihood of the realization of deferred tax assets, and reduces the carrying amount of these deferred tax assets by a valuation allowance to the extent it believes a portion will not be realized.
The Company considers many factors when assessing the likelihood of future realization of the deferred tax assets, including its recent cumulative earnings experience by taxing jurisdiction, expectations of future income, the carryforward periods available for tax reporting purposes, and other relevant factors.
The tax effects of temporary differences that give rise to significant portions of deferred tax assets and liabilities at December 31, 2013 and 2012 are as follows (in thousands):
## Table 0 ##
(1) Includes current deferred tax liabilities of $38 thousand and $0.8 million as of December 31, 2013 and 2012, respectively, which are reported in "Accrued expenses and other current liabilities" on the Consolidated Balance Sheets.
The valuation allowance on deferred tax assets of $173.6 million at December 31, 2013 includes $150.1 million related to U. S.  federal net operating loss carryforwards derived from equity transactions and $21.7 million related to international operations.
Additionally, since January 1, 2006, the Company has generated additional federal tax benefits of $235.5 million related to equity transactions that are not included in the deferred tax asset table above.
Pursuant to accounting guidance, these tax benefits related to equity deductions will be recognized by crediting paid in capital, if and when they are realized by reducing the Company's current income tax liability.
It is the practice and intention of the Company to reinvest the earnings of its non-U.
S.  subsidiaries in those operations.
Thus at December 31, 2013, no provision had been made for U. S.  taxes on approximately $4.9 billion of international earnings because such earnings are intended to be indefinitely reinvested outside of the United States.
Estimating the tax liability that would arise if these earnings were repatriated is not practicable at this time.
At December 31, 2013, the Company has approximately $576.0 million of state net operating loss carryforwards that expire mainly between December 31, 2020 and December 31,2033 , $130.0 million of foreign net operating loss carryforwards, of which $41.5 million expire between December 31, 2019 and December 31, 2020 and $3.7 million which expire between December 31, 2028 and December 31, 2030 , and $1.8 million of foreign capital allowance carryforwards that do not expire.
At December 31, 2013, the Company also had approximately $17.4 million of U. S.  research credit carryforwards that mainly expire by December 31, 2033 and are also subject to annual limitation.
Hologic, Inc.  Notes to Consolidated Financial Statements (continued) (In thousands, except per share data) failure of the Company to develop new products and product enhancements on a timely basis or within budget could harm the Company’s results of operations and financial condition.
For additional risks that may affect the Company’s business and prospects following completion of the merger, see “Risk Factors” in Item 1A of the Company’s Form 10-K for the year ended September 29, 2007.
Goodwill The preliminary purchase price allocation has resulted in goodwill of approximately $3,895,100.
The factors contributing to the recognition of this amount of goodwill are based upon several strategic and synergistic benefits that are expected to be realized from the combination.
These benefits include the expectation that the Company’s complementary products and technologies will create a leading women’s healthcare company with an enhanced presence in hospitals, private practices and healthcare organizations.
The Company also expects to realize substantial synergies through the use of Cytyc’s OB/GYN and breast surgeon sales channel to cross-sell the Company’s existing and future products.
The merger provides the Company broader channel coverage within the United States and expanded geographic reach internationally, as well as increased scale and scope for further expanding operations through product development and complementary strategic transactions.
Supplemental Unaudited Pro-forma Information The following unaudited pro forma information presents the consolidated results of operations of the Company and Cytyc as if the acquisitions had occurred at the beginning of fiscal 2007, with pro forma adjustments to give effect to amortization of intangible assets, an increase in interest expense on acquisition financing and certain other adjustments together with related tax effects:
## Table 1 ##
The $368,200 charge for acquired in-process research and development that was a direct result of the transaction is excluded from the unaudited pro forma information above.
The unaudited pro forma results are not necessarily indicative of the results that the Company would have attained had the acquisitions of Cytyc occurred at the beginning of the periods presented.
Prior to the close of the merger the Board of Directors of both Hologic and Cytyc approved a modification to certain outstanding equity awards for Cytyc employees.
The modification provided for the acceleration of vesting upon the close of Merger for those awards that did not provide for acceleration upon a change of control as part of the original terms of the award.
This modification was made so that the Company will not incur stock based compensation charges that it otherwise would have if the awards had continued to vest under their original terms.
Credit Agreement On October 22, 2007, Company and certain of its domestic subsidiaries, entered into a senior secured credit agreement with Goldman Sachs Credit Partners L. P.  and certain other lenders, (collectively, the “Lenders”).
Pursuant to the terms and conditions of the Credit Agreement, the Lenders have committed to provide senior secured financing in an aggregate amount of up to $2,550,000.
As of the closing of the Cytyc merger, the Company borrowed $2,350,000 under the credit facilities.
The decrease in net investment income yield attributable to the Financial Services Businesses’ general account excluding the Japanese operations’ portfolio for 2010 compared to 2009 was primarily due to a decrease in fixed maturity yields as a result of lower interest rates on floating rate investments from rate resets and lower fixed maturity reinvestment rates partially offset by an increase in other investment yields driven by favorable joint venture and limited partnership earnings driven by appreciation on the underlying assets.
The decrease in net investment income yield attributable to the non-Japanese operations’ portion of the Financial Services Businesses portfolio for 2009 compared to 2008 was primarily due to a decrease in fixed maturity yields as a result of lower interest rates on floating rate investments from rate resets and a shift in asset mix stemming from enterprise risk constraints.
Short-term yields also decreased as a result of lower short-term rates.
The following tables set forth the income yield and investment income, excluding realized investment gains (losses) and non-hedge accounting derivative results, for each major investment category of our Japanese operations’ general account for the periods indicated.
## Table 2 ##
(1) Yields are based on quarterly average carrying values except for fixed maturities, equity securities and securities lending activity.
Yields for fixed maturities are based on amortized cost.
Yields for equity securities are based on cost.
Yields for fixed maturities and short-term investments and cash equivalents are calculated net of liabilities and rebate expenses corresponding to securities lending activity.
Yields exclude investment income on assets other than those included in invested assets.
Prior periods’ yields are presented on a basis consistent with the current period presentation.
The decrease in yield on the Japanese insurance portfolio for 2010 compared to 2009 is primarily attributable to lower fixed maturity reinvestment rates and a lower short-term interest rate environment both in the U. S.  and Japan, as well less favorable results in joint ventures and limited partnerships.
The decrease in yield on the Japanese insurance portfolio for 2009 compared to 2008 is primarily attributable to lower fixed maturity reinvestment rates, including the reinvestment of proceeds realized from certain capital actions and a lower short-term interest rate environment both in the U. S.  and Japan.
The U. S.  dollar denominated fixed maturities that are not hedged to yen through third party derivative contracts provide a yield that is substantially higher than the yield on comparable Japanese fixed maturities.
The average value of U. S.  dollar denominated fixed maturities that are not hedged to yen through third party derivative contracts for the years ended December 31, 2010, and 2009, was approximately $12.3 billion and $10.4 billion, respectively, based on amortized cost.
For additional information regarding U. S.  dollar investments held in our Japanese insurance operations see, “—Results of Operations for Financial Services Businesses by Segment—International Insurance and Investments Division.
” Fixed Maturity Securities Investment Mix Our fixed maturity securities portfolio consists of publicly-traded and privately-placed debt securities across an array of industry categories.
The fixed maturity securities relating to our international insurance operations are primarily comprised of foreign government securities.
We manage our public portfolio to a risk profile directed or overseen by the Asset Liability Management and Risk Management groups and to a profile that also reflects the local market environments impacting both our domestic and international insurance portfolios.
The investment objectives for fixed maturity securities are consistent with those described above.
The total return that we earn on the portfolio will be reflected both as investment income and also as realized gains or losses on investments.
We use our private placement and asset-backed portfolios to enhance the diversification and yield of our overall fixed maturity portfolio.
Within our domestic portfolios, we maintain a private fixed income portfolio that is larger than the industry average as a percentage of total fixed income holdings.
Over the last several years, our investment staff has originated the majority of our annual private placement originations through direct borrower relationships.
Our origination capability offers the opportunity to lead transactions and gives us the opportunity for better terms, including covenants and call protection, and to take advantage of innovative deal structures.
businesses and other assets (net of cash divested).
We believe it is indicative of our ability to pay our quarterly dividends, repurchase common stock, fund acquisitions and other investments and, in the absence of refinancings, to repay our debt obligations.
Free cash flow is not intended to replace “Net cash provided by operating activities,” which is the most comparable GAAP measure.
However, we believe free cash flow gives investors useful insight into how we view our liquidity.
Nevertheless, the use of free cash flow as a liquidity measure has material limitations because it excludes certain expenditures that are required or that we have committed to, such as declared dividend payments and debt service requirements.
Our calculation of free cash flow and reconciliation to “Net cash provided by operating activities” is shown in the table below (in millions), and may not be calculated the same as similarly-titled measures presented by other companies:

<table><tr><td></td><td>2013</td><td>2012</td></tr><tr><td>Deferred tax assets/(liabilities):</td><td></td><td></td></tr><tr><td>Net operating loss carryforward — U.S.</td><td>263,994</td><td>244,016</td></tr><tr><td>Net operating loss carryforward — Foreign</td><td>21,660</td><td>19,638</td></tr><tr><td>Fixed assets</td><td>818</td><td>38</td></tr><tr><td>Investments</td><td>—</td><td>5,139</td></tr><tr><td>Accrued expenses</td><td>22,708</td><td>20,488</td></tr><tr><td>Stock-based compensation and other stock based payments</td><td>40,346</td><td>12,326</td></tr><tr><td>Other</td><td>33,530</td><td>15,881</td></tr><tr><td>Subtotal</td><td>383,056</td><td>317,526</td></tr><tr><td>Discount on convertible notes</td><td>-97,550</td><td>-68,594</td></tr><tr><td>Intangible assets and other</td><td>-356,669</td><td>-47,053</td></tr><tr><td>Less valuation allowance on deferred tax assets</td><td>-173,558</td><td>-175,594</td></tr><tr><td>Net deferred tax assets (liabilities)<sup>(1)</sup></td><td>$-244,721</td><td>$26,285</td></tr></table>
<table><tr><td>(approximate amounts in thousands except per share data)</td><td>2007</td></tr><tr><td>Net revenue</td><td>$1,472,400</td></tr><tr><td>Net income</td><td>$62,600</td></tr><tr><td>Net income per share—basic</td><td>$0.52</td></tr><tr><td>Net income per share—assuming dilution</td><td>$0.50</td></tr></table>
<table><tr><td></td><td colspan="6">Year Ended December 31,</td></tr><tr><td></td><td colspan="2">2010</td><td colspan="2">2009</td><td colspan="2">2008</td></tr><tr><td></td><td>Yield-1</td><td>Amount</td><td>Yield-1</td><td>Amount</td><td>Yield-1</td><td>Amount</td></tr><tr><td></td><td colspan="6">($ in millions)</td></tr><tr><td>Fixed maturities</td><td>2.81%</td><td>$1,733</td><td>2.88%</td><td>$1,519</td><td>2.95%</td><td>$1,314</td></tr><tr><td>Trading account assets supporting insurance liabilities</td><td>1.98</td><td>26</td><td>1.97</td><td>22</td><td>2.10</td><td>23</td></tr><tr><td>Equity securities</td><td>2.84</td><td>44</td><td>3.13</td><td>58</td><td>2.91</td><td>73</td></tr><tr><td>Commercial mortgage and other loans</td><td>4.63</td><td>175</td><td>4.85</td><td>167</td><td>4.76</td><td>144</td></tr><tr><td>Policy loans</td><td>3.85</td><td>72</td><td>3.91</td><td>63</td><td>3.92</td><td>50</td></tr><tr><td>Short-term investments and cash equivalents</td><td>0.24</td><td>4</td><td>0.62</td><td>11</td><td>2.26</td><td>21</td></tr><tr><td>Other investments</td><td>6.01</td><td>132</td><td>6.27</td><td>129</td><td>8.77</td><td>139</td></tr><tr><td>Gross investment income before investment expenses</td><td>2.97</td><td>2,186</td><td>3.05</td><td>1,969</td><td>3.21</td><td>1,764</td></tr><tr><td>Investment expenses</td><td>-0.15</td><td>-112</td><td>-0.16</td><td>-108</td><td>-0.19</td><td>-107</td></tr><tr><td>Total investment income</td><td>2.82%</td><td>$2,074</td><td>2.89%</td><td>$1,861</td><td>3.02%</td><td>$1,657</td></tr></table>

Question: Which year Ended December 31 is the Amount of Equity securities the highest?
Answer: 2008