The following is a summary of net investment income:
## Table 0 ##
Available-for-Sale securities distributed by type were as follows:
## Table 1 ##
## Table 2 ##
(1) Represents the amount of other-than-temporary impairment (‘‘OTTI’’) losses in AOCI.
Amount includes unrealized gains and losses on impaired securities subsequent to the initial impairment measurement date.
These amounts are included in gross unrealized gains and losses as of the end of the period.
As of December 31, 2014 and 2013, investment securities with a fair value of $1.3 billion and $2.3 billion, respectively, were pledged to meet contractual obligations under derivative contracts and short-term borrowings.
At December 31, 2014 and 2013, fixed maturity securities comprised approximately 84% and 85%, respectively, of Ameriprise Financial investments.
Rating agency designations are based on the availability of ratings from Nationally Recognized Statistical Rating Organizations (‘‘NRSROs’’), including Moody’s Investors Service (‘‘Moody’s’’), Standard & Poor’s Ratings Services (‘‘S&P’’) and Fitch Ratings Ltd.  (‘‘Fitch’’).
The Company uses the median of available ratings from Moody’s, S&P and Fitch, or, if fewer than three ratings are available, the lower rating is used.
When ratings from Moody’s, S&P and Fitch are unavailable, the Company may utilize ratings from other NRSROs or rate the securities internally.
At both December 31, 2014 and 2013, the Company’s internal analysts rated $1.4 billion of securities using criteria similar to those used by NRSROs.
The following table illustrates the pro forma effect on net income and earnings per share as if all outstanding and unvested stock options in 2005 were accounted for using estimated fair value.
## Table 3 ##
Income Taxes: We use an asset and liability approach to account for income taxes.
Our objective is to recognize the amount of taxes payable or refundable for the current year through charges or credits to the current tax provision, and to recognize deferred tax assets and liabilities for the future tax consequences resulting from temporary differences between the amounts reported in the consolidated financial statements and their respective tax bases.
The measurement of tax assets and liabilities is based on enacted tax laws and applicable tax rates.
The financial statement effects of a tax position are recognized when we believe it more likely than not that the position will be sustained.
A deferred tax valuation allowance is established if it is considered more likely than not that all or a portion of the deferred tax assets will not be realized.
Earnings Per Share: Basic earnings per share is calculated by dividing net income available to common shareholders by the weighted-average number of common shares outstanding for the period, which excludes unvested shares of restricted stock.
Diluted earnings per share is calculated by dividing net income available to common shareholders by the weighted-average number of common shares outstanding for the period and the shares representing the dilutive effect of stock options and awards and other equity-related financial instruments.
The effect of stock options and restricted stock outstanding is excluded from the calculation of diluted earnings per share in periods in which their effect would be antidilutive.
Special Purpose Entities: We are involved with various legal forms of special purpose entities, or SPEs, in the normal course of our business.
We use trusts to structure and sell certificated interests in pools of tax-exempt investment-grade assets principally to our mutual fund customers.
These trusts are recorded in our consolidated financial statements.
We transfer assets to these trusts, which are legally isolated from us, from our investment securities portfolio at adjusted book value.
The trusts finance the acquisition of these assets by selling certificated interests issued by the trusts to third-party investors.
The investment securities of the trusts are carried in investments securities available for sale at fair value.
The certificated interests are carried in other short-term borrowings at the amount owed to the third-party investors.
The interest revenue and interest expense generated by the investments and certificated interests, respectively, are recorded in net interest revenue when earned or incurred.
The majority of our sales in the U. S.  are conducted through strong, long-standing relationships with leading distributors and dedicated channel partners for water, gas and electric markets.
Internationally, direct sales are often made in markets without established distribution channels, however, some distribution channels are used in more developed markets.
With large utilities and government programs a more direct sales approach, with key account management, is employed.
We estimate our served market size in this sector to be approximately $12 billion.
Macro growth drivers include increasing regulation and worldwide movement towards smart grid implementation.
Water scarcity and conservation, as well as the need to prevent revenue loss (via inaccurate meter readings, leaks or theft) are among the drivers of smart meter technologies.
Our Sensus-branded meters are well positioned in the smart metering sector, the fastest growing sector of the global meter industry.
We set ourselves apart in the industry by focusing on new product development and service offerings that are driving tangible savings of non-revenue water through improved meter accuracy, reduced theft and identification of leaks.
Our key competitors within the Sensus segment include Itron, Badger Meter, Landys & Gyr, Neptune (Roper) and Elster (Honeywell).
Geographic Profile The table below illustrates the annual revenue and percentage of revenue by geographic area for each of the three years ended December 31.
## Table 4 ##
In addition to the traditional markets of the United States and Europe, opportunities in emerging markets within Asia Pacific, Eastern Europe, Latin America and other countries are growing.
Revenue derived from emerging markets comprised 21% of our revenue in each of the last three years.
The table below illustrates the property, plant & equipment and percentage of property, plant & equipment by geographic area for each of the three years ended December 31.
## Table 5 ##
Supply and Seasonality We have a global manufacturing footprint, with production facilities in Europe, North America, Latin America, and Asia.
Our inventory management and distribution practices seek to minimize inventory holding periods by striving to take delivery of the inventory and manufacturing as close as possible to the sale or distribution of products to our customers.
All of our businesses require various parts and raw materials, of which the availability and prices may fluctuate.
Parts and raw materials commonly used in our products include motors, fabricated parts, castings, bearings, seals, nickel, copper, aluminum, plastics, PCBs and electronic components.
While we may recover some cost increases through operational improvements, we are still exposed to some pricing risk, including increased pricing risk due to proposed duty and tariff assessments by the United States on foreign imports.
We attempt to control costs through fixed- priced contracts with suppliers and various other programs, such as our global procurement initiative.
Our business relies on third-party suppliers, contract manufacturing and commodity markets to secure raw materials, parts and components used in our products.
We typically acquire materials and components through a

<table><tr><td></td><td colspan="3">Years Ended December 31,</td></tr><tr><td></td><td>2014</td><td>2013</td><td>2012</td></tr><tr><td></td><td colspan="3">(in millions)</td></tr><tr><td>Investment income on fixed maturities</td><td>$1,479</td><td>$1,575</td><td>$1,768</td></tr><tr><td>Net realized gains</td><td>37</td><td>7</td><td>7</td></tr><tr><td>Affordable housing partnerships</td><td>-25</td><td>-12</td><td>-25</td></tr><tr><td>Other</td><td>93</td><td>99</td><td>73</td></tr><tr><td>Consolidated investment entities</td><td>157</td><td>220</td><td>110</td></tr><tr><td>Total net investment income</td><td>$1,741</td><td>$1,889</td><td>$1,933</td></tr></table>
<table><tr><td></td><td colspan="5">December 31, 2014</td></tr><tr><td>Description of Securities</td><td>AmortizedCost</td><td>GrossUnrealizedGains</td><td>GrossUnrealizedLosses</td><td>Fair Value</td><td>NoncreditOTTI<sup>-1</sup></td></tr><tr><td></td><td colspan="5">(in millions)</td></tr><tr><td>Corporate debt securities</td><td>$15,742</td><td>$1,482</td><td>$-59</td><td>$17,165</td><td>$3</td></tr><tr><td>Residential mortgage backed securities</td><td>6,099</td><td>168</td><td>-60</td><td>6,207</td><td>-15</td></tr><tr><td>Commercial mortgage backed securities</td><td>2,513</td><td>120</td><td>-3</td><td>2,630</td><td>—</td></tr><tr><td>Asset backed securities</td><td>1,417</td><td>59</td><td>-6</td><td>1,470</td><td>—</td></tr><tr><td>State and municipal obligations</td><td>2,008</td><td>257</td><td>-26</td><td>2,239</td><td>—</td></tr><tr><td>U.S. government and agencies obligations</td><td>43</td><td>4</td><td>—</td><td>47</td><td>—</td></tr><tr><td>Foreign government bonds and obligations</td><td>236</td><td>21</td><td>-6</td><td>251</td><td>—</td></tr><tr><td>Common stocks</td><td>8</td><td>10</td><td>—</td><td>18</td><td>5</td></tr><tr><td>Total</td><td>$28,066</td><td>$2,121</td><td>$-160</td><td>$30,027</td><td>$-7</td></tr></table>
<table><tr><td></td><td colspan="5">December 31, 2013</td></tr><tr><td>Description of Securities</td><td>AmortizedCost</td><td>GrossUnrealizedGains</td><td>GrossUnrealizedLosses</td><td>Fair Value</td><td>NoncreditOTTI<sup>-1</sup></td></tr><tr><td></td><td colspan="5">(in millions)</td></tr><tr><td>Corporate debt securities</td><td>$16,233</td><td>$1,330</td><td>$-97</td><td>$17,466</td><td>$3</td></tr><tr><td>Residential mortgage backed securities</td><td>6,114</td><td>147</td><td>-137</td><td>6,124</td><td>-33</td></tr><tr><td>Commercial mortgage backed securities</td><td>2,612</td><td>141</td><td>-12</td><td>2,741</td><td>—</td></tr><tr><td>Asset backed securities</td><td>1,459</td><td>53</td><td>-8</td><td>1,504</td><td>—</td></tr><tr><td>State and municipal obligations</td><td>2,132</td><td>106</td><td>-78</td><td>2,160</td><td>—</td></tr><tr><td>U.S. government and agencies obligations</td><td>47</td><td>5</td><td>—</td><td>52</td><td>—</td></tr><tr><td>Foreign government bonds and obligations</td><td>235</td><td>18</td><td>-8</td><td>245</td><td>—</td></tr><tr><td>Common stocks</td><td>7</td><td>11</td><td>—</td><td>18</td><td>4</td></tr><tr><td>Total</td><td>$28,839</td><td>$1,811</td><td>$-340</td><td>$30,310</td><td>$-26</td></tr></table>
<table><tr><td>Year ended December 31,</td><td>2005</td></tr><tr><td>(In millions, except per share amounts)</td><td></td></tr><tr><td>Net income as reported</td><td>$838</td></tr><tr><td>Add: Stock option compensation expense included in reported net income, net of related taxes</td><td>20</td></tr><tr><td>Deduct: Total stock option compensation expense determined under fair value method for all awards, net of related taxes</td><td>-27</td></tr><tr><td>Pro forma net income</td><td>$831</td></tr><tr><td>Earnings per share:</td><td></td></tr><tr><td>Basic—as reported</td><td>$2.53</td></tr><tr><td>Basic—pro forma</td><td>2.51</td></tr><tr><td>Diluted—as reported</td><td>2.50</td></tr><tr><td>Diluted—pro forma</td><td>2.48</td></tr></table>
<table><tr><td></td><td colspan="6">Revenue</td></tr><tr><td>(in millions)</td><td colspan="2">2016</td><td colspan="2">2015</td><td colspan="2">2014</td></tr><tr><td></td><td>$ Amount</td><td>% of Total</td><td>$ Amount</td><td>% of Total</td><td>$ Amount</td><td>% of Total</td></tr><tr><td>United States</td><td>$1,574</td><td>42%</td><td>$1,490</td><td>41%</td><td>$1,477</td><td>38%</td></tr><tr><td>Europe</td><td>1,195</td><td>31%</td><td>1,179</td><td>32%</td><td>1,379</td><td>35%</td></tr><tr><td>Asia Pacific</td><td>518</td><td>14%</td><td>482</td><td>13%</td><td>478</td><td>12%</td></tr><tr><td>Other</td><td>484</td><td>13%</td><td>502</td><td>14%</td><td>582</td><td>15%</td></tr><tr><td>Total</td><td>$3,771</td><td></td><td>$3,653</td><td></td><td>$3,916</td><td></td></tr></table>
<table><tr><td></td><td colspan="6">Property, Plant & Equipment</td></tr><tr><td>(in millions)</td><td colspan="2">2016</td><td colspan="2">2015</td><td colspan="2">2014</td></tr><tr><td></td><td>$ Amount</td><td>% of Total</td><td>$ Amount</td><td>% of Total</td><td>$ Amount</td><td>% of Total</td></tr><tr><td>United States</td><td>$255</td><td>41%</td><td>$168</td><td>38%</td><td>$180</td><td>39%</td></tr><tr><td>Europe</td><td>237</td><td>39%</td><td>189</td><td>43%</td><td>206</td><td>45%</td></tr><tr><td>Asia Pacific</td><td>87</td><td>14%</td><td>56</td><td>13%</td><td>53</td><td>11%</td></tr><tr><td>Other</td><td>37</td><td>6%</td><td>26</td><td>6%</td><td>22</td><td>5%</td></tr><tr><td>Total</td><td>$616</td><td></td><td>$439</td><td></td><td>$461</td><td></td></tr></table>

Question: What's the difference of Net realized gains between 2014 and 2013? (in millions)
Answer: 30