The following table provides a historical perspective regarding the accrual and payment of our benefits payable, excluding military services.
Components of the total incurred claims for each year include amounts accrued for current year estimated benefit expenses as well as adjustments to prior year estimated accruals.
## Table 0 ##
Amounts incurred related to prior years vary from previously estimated liabilities as the claims ultimately are settled.
Negative amounts reported for incurred related to prior years result from claims being ultimately settled for amounts less than originally estimated (favorable development).
As summarized in the previous table, claim reserve balances at December 31, 2006 ultimately settled during 2007 for $242.9 million less than the amounts originally estimated.
During 2006, claim reserve balances at December 31, 2005 ultimately settled for $179.0 million less than the amounts originally estimated.
The $63.9 million change in the amounts incurred related to prior years for 2007 as compared to 2006 primarily relates to favorable development experienced in our Medicare operations.
As previously described, our key assumptions consist of trend factors and completion factors using an assumption of moderately adverse conditions.
In our Medicare operations, both our trend factor and completion factor assumptions at December 31, 2006 ultimately developed favorable versus our original estimate primarily due to changes in estimates associated with our 2006 Medicare Part D reconciliation and the growth in our Medicare business.
First year Medicare Part D enrollment and eligibility issues in 2006 led to actual claim settlements with other health plans and states during 2007 for amounts less than originally estimated.
Similar adjustments in the future are not expected to be as significant due to the program’s operational improvement in 2007.
During 2006, claim reserve balances at December 31, 2005 ultimately settled during 2006 for $179.0 million less than the amounts originally estimated.
During 2005, claim reserve balances at December 31, 2004 ultimately settled for $72.9 million less than the amounts originally estimated.
This $106.1 million change in the amounts incurred related to prior years for 2006 as compared to 2005 primarily was attributable to both our Medicare and commercial lines of business.
In each of these lines of business, both our trend factor and completion factor assumptions at December 31, 2005 ultimately developed favorable versus our original estimate primarily due to (1) the utilization of hospital and physician services during the latter half of 2005 ultimately being lower than estimated, (2) the impact of hurricanes in Florida and Louisiana in the second half of 2005 on both utilization of services and claims processing, (3) significant growth in our Medicare PFFS product, (4) reductions in receipt cycle times driven by an increase in electronic claims submissions, and (5) an increase in claim overpayment recovery levels versus our historical overpayment recovery rate.
Gross unrealized losses and fair values aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position were as follows at December 31, 2010:
## Table 1 ##
In April 2009, the Financial Accounting Standards Board, or the FASB, issued new guidance to address concerns about (1) measuring the fair value of financial instruments when the markets become inactive and quoted prices may reflect distressed transactions and (2) recording impairment charges on investments in debt securities.
The new guidance highlighted and expanded on the factors that should be considered in estimating fair value when the volume and level of activity for a financial asset or liability has significantly decreased and required new disclosures relating to fair value measurement inputs and valuation techniques (including changes in inputs and valuation techniques).
In addition, new guidance regarding recognition and presentation of otherthan-temporary impairments changed (1) the trigger for determining whether an other-than-temporary impairment exists and (2) the amount of an impairment charge to be recorded in earnings.
We adopted the provisions of the new guidance for the quarter ended June 30, 2009.
Refer to Note 4 and Note 5 to the consolidated financial statements included in Item 8.
—Financial Statements and Supplementary Data for disclosures related to the implementation of the new guidance.
Under the revised other-than-temporary impairment model for debt securities held, we recognize an impairment loss in income in an amount equal to the full difference between the amortized cost basis and the fair value when we have the intent to sell the debt security or it is more likely than not we will be required to sell the debt security before recovery of our amortized cost basis.
However, if we do not intend to sell the debt security, we evaluate the expected cash flows to be received as compared to amortized cost and determine if a credit loss has occurred.
In the event of a credit loss, only the amount of the impairment associated with the credit loss is recognized currently in income with the remainder of the loss recognized in other comprehensive income.
When we do not intend to sell a security in an unrealized loss position, potential other-than-temporary impairment is considered using a variety of factors, including the length of time and extent to which the fair value has been less than cost; adverse conditions specifically related to the industry, geographic area or financial condition of the issuer or underlying collateral of a security; payment structure of the security; changes in credit rating of the security by the rating agencies; the volatility of the fair value changes; and changes in fair value of
Humana Inc.  NOTES TO CONSOLIDATED FINANCIAL STATEMENTS—(Continued) 123 15.
STOCKHOLDERS’ EQUITY As discussed in Note 2, we elected to early adopt new guidance related to accounting for employee share-based payments prospectively effective January 1, 2016.
The adoption of this new guidance resulted in the recognition of approximately $20 million of tax benefits in net income in our consolidated statement of income for the three months ended March 31, 2016 that had previously been recorded as additional paid-in capital in our consolidated balance sheet.
Dividends The following table provides details of dividend payments, excluding dividend equivalent rights, in 2014, 2015, and 2016 under our Board approved quarterly cash dividend policy:
## Table 2 ##
Under the terms of the Merger Agreement, we agreed with Aetna that our quarterly dividend would not exceed $0.29 per share prior to the closing or termination of the Merger.
On October 26, 2016, the Board declared a cash dividend of $0.29 per share that was paid on January 27, 2017 to stockholders of record on January 12, 2017, for an aggregate amount of $43 million.
On February 14, 2017, following the termination of the Merger Agreement, the Board declared a cash dividend of $0.40 per share, to be paid on April 28, 2017, to the stockholders of record on March 31, 2017.
Declaration and payment of future quarterly dividends is at the discretion of our Board and may be adjusted as business needs or market conditions change.
Stock Repurchases In September 2014, our Board of Directors replaced a previous share repurchase authorization of up to $1 billion (of which $816 million remained unused) with an authorization for repurchases of up to $2 billion of our common shares exclusive of shares repurchased in connection with employee stock plans, which expired on December 31, 2016.
Under the share repurchase authorization, shares may have been purchased from time to time at prevailing prices in the open market, by block purchases, through plans designed to comply with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended, or in privately-negotiated transactions (including pursuant to accelerated share repurchase agreements with investment banks), subject to certain regulatory restrictions on volume, pricing, and timing.
Pursuant to the Merger Agreement, after July 2, 2015, we were prohibited from repurchasing any of our outstanding securities without the prior written consent of Aetna, other than repurchases of shares of our common stock in connection with the exercise of outstanding stock options or the vesting or settlement of outstanding restricted stock awards.
Accordingly, as announced on July 3, 2015, we suspended our share repurchase program.

<table><tr><td></td><td>2007</td><td>2006</td><td>2005</td></tr><tr><td></td><td colspan="3">(in thousands)</td></tr><tr><td>Balances at January 1</td><td>$1,979,733</td><td>$1,334,716</td><td>$1,074,310</td></tr><tr><td>Acquisitions</td><td>41,029</td><td>21,198</td><td>37,375</td></tr><tr><td>Incurred related to:</td><td></td><td></td><td></td></tr><tr><td>Current year</td><td>18,015,247</td><td>15,374,855</td><td>9,635,435</td></tr><tr><td>Prior years</td><td>-242,922</td><td>-178,998</td><td>-72,868</td></tr><tr><td>Total incurred</td><td>17,772,325</td><td>15,195,857</td><td>9,562,567</td></tr><tr><td>Paid related to:</td><td></td><td></td><td></td></tr><tr><td>Current year</td><td>-16,012,828</td><td>-13,532,139</td><td>-8,392,628</td></tr><tr><td>Prior years</td><td>-1,424,798</td><td>-1,039,899</td><td>-946,908</td></tr><tr><td>Total paid</td><td>-17,437,626</td><td>-14,572,038</td><td>-9,339,536</td></tr><tr><td>Balances at December 31</td><td>$2,355,461</td><td>$1,979,733</td><td>$1,334,716</td></tr></table>
<table><tr><td></td><td colspan="2">Less than 12 months</td><td colspan="2">12 months or more</td><td colspan="2">Total</td></tr><tr><td></td><td> Fair  Value</td><td>Gross Unrealized Losses</td><td> Fair  Value</td><td>Gross Unrealized Losses</td><td> Fair  Value</td><td>Gross Unrealized Losses</td></tr><tr><td></td><td colspan="6">(in thousands)</td></tr><tr><td> December 31, 2010</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>U.S. Treasury and other U.S. government corporations and agencies:</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>U.S. Treasury and agency obligations</td><td>$141,766</td><td>$-615</td><td>$0</td><td>$0</td><td>$141,766</td><td>$-615</td></tr><tr><td>Mortgage-backed securities</td><td>110,358</td><td>-1,054</td><td>5,557</td><td>-119</td><td>115,915</td><td>-1,173</td></tr><tr><td>Tax-exempt municipal securities</td><td>1,168,221</td><td>-33,218</td><td>97,809</td><td>-10,401</td><td>1,266,030</td><td>-43,619</td></tr><tr><td>Mortgage-backed securities:</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Residential</td><td>0</td><td>0</td><td>32,671</td><td>-2,675</td><td>32,671</td><td>-2,675</td></tr><tr><td>Commercial</td><td>0</td><td>0</td><td>2,752</td><td>-171</td><td>2,752</td><td>-171</td></tr><tr><td>Asset-backed securities</td><td>17,069</td><td>-42</td><td>283</td><td>-2</td><td>17,352</td><td>-44</td></tr><tr><td>Corporate debt securities</td><td>383,677</td><td>-9,572</td><td>31,464</td><td>-4,138</td><td>415,141</td><td>-13,710</td></tr><tr><td>Total debt securities</td><td>$1,821,091</td><td>$-44,501</td><td>$170,536</td><td>$-17,506</td><td>$1,991,627</td><td>$-62,007</td></tr></table>
<table><tr><td>PaymentDate</td><td>Amountper Share</td><td>TotalAmount (in millions)</td></tr><tr><td>2014</td><td>$1.10</td><td>$170</td></tr><tr><td>2015</td><td>$1.14</td><td>$170</td></tr><tr><td>2016</td><td>$1.16</td><td>$172</td></tr></table>

Question: What is the column number of the section where the value of Total debt securities is negative for Less than 12 months as of December 31, 2010?
Answer: 2