Asset-backed securities also include collateralized debt obligations backed by sub-prime mortgage loans at an aggregate cost of $20 million with an estimated fair value of $10 million at December 31, 2008 and an aggregate cost of $63 million with an estimated fair value of $47 million at December 31, 2007, which are not included in the tables above.
Commercial Mortgage-Backed Securities.
There have been disruptions in the commercial mortgage-backed securities market due to market perceptions that default rates will increase in part due weakness in commercial real estate market fundamentals and due in part to relaxed underwriting standards by some originators of commercial mortgage loans within the more recent vintage years (i. e.  2006 and later).
These factors have caused a pull-back in market liquidity, increased spreads and repricing of risk, which has led to an increase in unrealized losses since third quarter 2008.
Based upon the analysis of the Company’s exposure to commercial mortgage-backed securities, the Company expects to receive payments in accordance with the contractual terms of the securities.
At December 31, 2008 and 2007, the Company’s holdings in commercial mortgage-backed securities was $12.6 billion and $17.0 billion, respectively, at estimated fair value.
At December 31, 2008 and 2007, $11.8 billion and $14.9 billion, respectively, of the estimated fair value, or 93% and 88%, respectively, of the commercial mortgage-backed securities were rated Aaa/AAA by Moody’s, S&P, or Fitch.
At December 31, 2008, the rating distribution of the Company’s commercial mortgage-backed securities holdings was as follows: 93% Aaa, 4% Aa, 1% A, 1% Baa, and 1% Ba or below.
At December 31, 2008, 84% of the holdings are in the 2005 and prior vintage years.
At December 31, 2008, the Company had no exposure to CMBX securities and its holdings of commercial real estate debt obligations securities was $121 million at estimated fair value.
The weighted average credit enhancement of the Company’s commercial mortgage-backed securities holdings at December 31, 2008 was 26%.
This credit enhancement percentage represents the current weighted average estimated percentage of outstanding capital structure subordinated to the Company’s investment holding that is available to absorb losses before the security incurs the first dollar of loss of principal.
The credit protection does not include any equity interest or property value in excess of outstanding debt.
The following table shows the Company’s exposure to commercial mortgage-backed securities by credit quality and by vintage year:
## Table 0 ##
December 31, 2007
## Table 1 ##
Securities Lending The Company participates in securities lending programs whereby blocks of securities, which are included in fixed maturity securities, and short-term investments are loaned to third parties, primarily major brokerage firms and commercial banks.
The Company generally requires collateral equal to 102% of the current estimated fair value of the loaned securities to be obtained at the inception of a loan, and maintained at a level greater than or equal to 100% for the duration of the loan.
During the extraordinary market events occurring in the fourth quarter of 2008, the Company, in limited instances, accepted collateral less than 102% at the inception of certain loans, but never less than 100%, of the estimated fair value of such loaned securities.
These loans involved U. S.  Government Treasury Bills which are considered to have limited variation in their estimated fair value during the term of the loan.
Securities with a cost or amortized cost of $20.8 billion and $41.1 billion and an estimated fair value of $22.9 billion and $42.1 billion were on loan under the program at December 31, 2008 and 2007, respectively.
Securities loaned under such transactions may be sold or repledged by the transferee.
The Company was liable for cash collateral under its control of $23.3 billion and $43.3 billion at December 31, 2008 and 2007, respectively.
Of this $23.3 billion of cash collateral at December 31, 2008, $5.1 billion was on open terms, meaning that the related loaned security could be returned to the Company on the next business day requiring return of cash collateral and $14.7 billion and $3.5 billion, respectively were due within 30 days and 60 days.
The estimated fair value of the securities related to the cash collateral on open at
Liquidity and Capital Liquidity and capital are managed to preserve stable, reliable and cost-effective sources of cash to meet all current and future financial obligations and are provided by a variety of sources, including a portfolio of liquid assets, a diversified mix of short- and long-term funding sources from the wholesale financial markets and the ability to borrow through committed credit facilities.
The Holding Company is an active participant in the global financial markets through which it obtains a significant amount of funding.
These markets, which serve as cost-effective sources of funds, are critical components of the Holding Company’s liquidity and capital management.
Decisions to access these markets are based upon relative costs, prospective views of balance sheet growth and a targeted liquidity profile and capital structure.
A disruption in the financial markets could limit the Holding Company’s access to liquidity.
See “Extraordinary Market Conditions.
” The Holding Company’s ability to maintain regular access to competitively priced wholesale funds is fostered by its current high credit ratings from the major credit rating agencies.
Management views its capital ratios, credit quality, stable and diverse earnings streams, diversity of liquidity sources and its liquidity monitoring procedures as critical to retaining high credit ratings.
See “The Company — Capital — Rating Agencies.
” Liquidity is monitored through the use of internal liquidity risk metrics, including the composition and level of the liquid asset portfolio, timing differences in short-term cash flow obligations, access to the financial markets for capital and debt transactions and exposure to contingent draws on the Holding Company’s liquidity.
Liquidity and Capital Sources Dividends.
The primary source of the Holding Company’s liquidity is dividends it receives from its insurance subsidiaries.
The Holding Company’s insurance subsidiaries are subject to regulatory restrictions on the payment of dividends imposed by the regulators of their respective domiciles.
The dividend limitation for U. S.  insurance subsidiaries is generally based on the surplus to policyholders as of the immediately preceding calendar year and statutory net gain from operations for the immediately preceding calendar year.
Statutory accounting practices, as prescribed by insurance regulators of various states in which the Company conducts business, differ in certain respects from accounting principles used in financial statements prepared in conformity with GAAP.
The significant differences relate to the treatment of DAC, certain deferred income tax, required investment reserves, reserve calculation assumptions, goodwill and surplus notes.
Management of the Holding Company cannot provide assurances that the Holding Company’s insurance subsidiaries will have statutory earnings to support payment of dividends to the Holding Company in an amount sufficient to fund its cash requirements and pay cash dividends and that the applicable insurance departments will not disapprove any dividends that such insurance subsidiaries must submit for approval.
The table below sets forth the dividends permitted to be paid by the respective insurance subsidiary without insurance regulatory approval and the respective dividends paid:
## Table 2 ##
(1) Reflects dividend amounts that may be paid during 2009 without prior regulatory approval.
However, if paid before a specified date during 2009, some or all of such dividends may require regulatory approval.
(2) Includes amounts paid including those requiring regulatory approval.
(3) Reflects dividend amounts that could have been paid during the relevant year without prior regulatory approval.
(4) Consists of shares of RGA stock distributed by Metropolitan Life Insurance Company to the Holding Company as an in-kind dividend of $1,318 million.
(5) Includes shares of an affiliate distributed to the Holding Company as an in-kind dividend of $164 million.
(6) Includes a return of capital of $404 million as approved by the applicable insurance department, of which $350 million was paid to the Holding Company.
In the fourth quarter of 2008, MICC declared and paid an ordinary dividend of $500 million to the Holding Company.
In the third quarter of 2008, MLIC used its otherwise ordinary dividend capacity through a non-cash dividend in conjunction with the RGA split-off as approved by the New York Insurance Commissioner.
Under New York State Insurance Law, MLIC is permitted, without prior insurance regulatory clearance, to pay stockholder dividends to the Holding Company as long as the aggregate amount of all such dividends in any calendar year does not exceed the lesser of: (i) 10% of its surplus to policyholders as of the end of the immediately preceding calendar year; or (ii) its statutory net gain from operations for the immediately preceding calendar year (excluding realized capital gains).
MLIC will be permitted to pay a cash dividend to the Holding Company in excess of the lesser of such two amounts only if it files notice of its intention to declare such a dividend and the amount thereof with the Superintendent and the Superintendent does not disapprove the distribution within 30 days of its filing.
For the year ended December 31, 2008, $235 million in dividends from other subsidiaries were paid to the Holding Company.
For the year ended December 31, 2007, $190 million in dividends from other subsidiaries were paid, of which $176 million were returns of capital, to the Holding Company.
Liquid Assets.
An integral part of the Holding Company’s liquidity management is the amount of liquid assets it holds.
Liquid assets include cash, cash equivalents, short-term investments and publicly-traded securities.
Liquid assets exclude cash collateral received under the Company’s securities lending program that has been reinvested in cash, cash equivalents, short-term investments and publiclytraded securities.
At December 31, 2008 and 2007, the Holding Company had $2.7 billion and $2.3 billion in liquid assets, respectively.
At December 31, 2008, the Holding Company had pledged $0.8 billion of liquid assets under collateral support agreements as described in
STOCK PERFORMANCE GRAPH This performance graph shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or otherwise subject to the liabilities under that Section and shall not be deemed to be incorporated by reference into any filing of Tractor Supply Company under the Securities Act of 1933, as amended, or the Exchange Act.
The following graph compares the cumulative total stockholder return on our common stock from December 28, 2013 to December 29, 2018 (the Company’s fiscal year-end), with the cumulative total returns of the S&P 500 Index and the S&P Retail Index over the same period.
The comparison assumes that $100 was invested on December 28, 2013, in our common stock and in each of the foregoing indices and in each case assumes reinvestment of dividends.
The historical stock price performance shown on this graph is not indicative of future performance.
## Table 3 ##

<table><tr><td></td><td colspan="12"> December 31, 2008</td></tr><tr><td></td><td colspan="2"> Aaa</td><td colspan="2"> Aa</td><td colspan="2"> A</td><td colspan="2"> Baa</td><td colspan="2"> Below   Investment   Grade</td><td colspan="2"> Total</td></tr><tr><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td></tr><tr><td></td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td></tr><tr><td></td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td></tr><tr><td></td><td colspan="12"> (In millions)</td></tr><tr><td>2003 & Prior</td><td>$5,428</td><td>$4,975</td><td>$424</td><td>$272</td><td>$213</td><td>$124</td><td>$51</td><td>$24</td><td>$42</td><td>$17</td><td>$6,158</td><td>$5,412</td></tr><tr><td>2004</td><td>2,630</td><td>2,255</td><td>205</td><td>100</td><td>114</td><td>41</td><td>47</td><td>11</td><td>102</td><td>50</td><td>3,098</td><td>2,457</td></tr><tr><td>2005</td><td>3,403</td><td>2,664</td><td>187</td><td>49</td><td>40</td><td>13</td><td>5</td><td>1</td><td>18</td><td>10</td><td>3,653</td><td>2,737</td></tr><tr><td>2006</td><td>1,825</td><td>1,348</td><td>110</td><td>39</td><td>25</td><td>14</td><td>94</td><td>36</td><td>—</td><td>—</td><td>2,054</td><td>1,437</td></tr><tr><td>2007</td><td>999</td><td>535</td><td>43</td><td>28</td><td>63</td><td>28</td><td>10</td><td>9</td><td>—</td><td>—</td><td>1,115</td><td>600</td></tr><tr><td>2008</td><td>1</td><td>1</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>1</td><td>1</td></tr><tr><td>Total</td><td>$14,286</td><td>$11,778</td><td>$969</td><td>$488</td><td>$455</td><td>$220</td><td>$207</td><td>$81</td><td>$162</td><td>$77</td><td>$16,079</td><td>$12,644</td></tr></table>
<table><tr><td></td><td colspan="12"> December 31, 2007</td></tr><tr><td></td><td colspan="2"> Aaa</td><td colspan="2"> Aa</td><td colspan="2"> A</td><td colspan="2"> Baa</td><td colspan="2"> Below   Investment   Grade</td><td colspan="2"> Total</td></tr><tr><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td><td> Cost or </td><td></td></tr><tr><td></td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td><td> Amortized </td><td> Fair </td></tr><tr><td></td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td><td> Cost</td><td> Value</td></tr><tr><td></td><td colspan="12"> (In millions)</td></tr><tr><td>2003 & Prior</td><td>$5,442</td><td>$5,500</td><td>$504</td><td>$512</td><td>$339</td><td>$342</td><td>$94</td><td>$92</td><td>$42</td><td>$43</td><td>$6,421</td><td>$6,489</td></tr><tr><td>2004</td><td>1,738</td><td>1,749</td><td>156</td><td>148</td><td>106</td><td>100</td><td>47</td><td>34</td><td>111</td><td>101</td><td>2,158</td><td>2,132</td></tr><tr><td>2005</td><td>3,154</td><td>3,166</td><td>212</td><td>198</td><td>50</td><td>48</td><td>5</td><td>4</td><td>76</td><td>61</td><td>3,497</td><td>3,477</td></tr><tr><td>2006</td><td>2,767</td><td>2,813</td><td>120</td><td>116</td><td>34</td><td>34</td><td>121</td><td>118</td><td>10</td><td>10</td><td>3,052</td><td>3,091</td></tr><tr><td>2007</td><td>1,680</td><td>1,672</td><td>91</td><td>87</td><td>37</td><td>36</td><td>10</td><td>9</td><td>—</td><td>—</td><td>1,818</td><td>1,804</td></tr><tr><td>Total</td><td>$14,781</td><td>$14,900</td><td>$1,083</td><td>$1,061</td><td>$566</td><td>$560</td><td>$277</td><td>$257</td><td>$239</td><td>$215</td><td>$16,946</td><td>$16,993</td></tr></table>
<table><tr><td></td><td rowspan="2"> 2009  Permitted w/o   Approval -1</td><td colspan="3"> 2008</td><td colspan="3"> 2007</td></tr><tr><td> Company</td><td> Paid -2</td><td></td><td> Permitted w/o   Approval -3</td><td> Paid -2</td><td></td><td> Permitted w/o   Approval -3</td></tr><tr><td></td><td colspan="7"> (In millions)</td></tr><tr><td>Metropolitan Life Insurance Company</td><td>$552</td><td>$1,318</td><td>-4</td><td>$1,299</td><td>$500</td><td></td><td>$919</td></tr><tr><td>MetLife Insurance Company of Connecticut</td><td>$714</td><td>$500</td><td></td><td>$1,026</td><td>$690</td><td>-6</td><td>$690</td></tr><tr><td>Metropolitan Tower Life Insurance Company</td><td>$88</td><td>$277</td><td>-5</td><td>$113</td><td>$—</td><td></td><td>$104</td></tr><tr><td>Metropolitan Property and Casualty Insurance Company</td><td>$9</td><td>$300</td><td></td><td>$—</td><td>$400</td><td></td><td>$16</td></tr></table>
<table><tr><td></td><td>12/28/2013</td><td>12/27/2014</td><td>12/26/2015</td><td>12/31/2016</td><td>12/30/2017</td><td>12/29/2018</td></tr><tr><td>Tractor Supply Company</td><td>$100.00</td><td>$104.11</td><td>$115.45</td><td>$103.33</td><td>$103.67</td><td>$117.18</td></tr><tr><td>S&P 500</td><td>$100.00</td><td>$115.76</td><td>$116.64</td><td>$129.55</td><td>$157.84</td><td>$149.63</td></tr><tr><td>S&P Retail Index</td><td>$100.00</td><td>$111.18</td><td>$140.22</td><td>$148.53</td><td>$193.68</td><td>$217.01</td></tr></table>

Question: What is the difference between the greatest Aaa in 2003 and 2004 for cost? (in million)
Answer: 2798