Based on 42.7 million, 44.7 million, 47.5 million, 51.4 million and 53.7 million common shares outstanding for December 31, 2015, 2014, 2013, 2012 and 2011, respectively.
Other Income (Expense). We recorded other income of $60.4 million and $18.4 million in 2015 and 2014, respectively, and other expense of $5.5 million in 2013. The changes were primarily the result of fluctuations in foreign currency exchange rates for the corresponding periods.
Net realized capital losses were $184.1 million in 2015 and net realized capital gains were $84.0 million and $300.2 million in 2014 and 2013, respectively. In 2015, we recorded $102.2 million of other-than-temporary impairments, $45.6 million of net losses from fair value re-measurements and $36.3 million of net realized capital losses from sales on our fixed maturity and equity securities. The fixed maturity and equity sales for 2015 related primarily to adjusting the portfolios for overall market changes and individual credit shifts. In 2014, we recorded $121.7 million of net realized capital gains due to fair value re-measurements on fixed maturity and equity securities and $1.9 million of net realized capital gains from sales of fixed maturity and equity securities, partially offset by $39.5 million of other-than-temporary impairments. In 2013, we recorded $258.9 million of net realized capital gains due to fair value re-measurements on fixed maturity and equity securities and $42.4 million of net realized capital gains from sales of fixed maturity and equity securities, partially offset by $1.1 million of other-than-temporary impairments. The fixed maturity and equity sales in 2014 and 2013 related primarily to adjusting the portfolios for overall market changes and individual credit shifts along with maintaining a balanced foreign currency exposure.
The U.S. Reinsurance operation writes property and casualty reinsurance and specialty lines of business, including Marine, Aviation, Surety and A&H business, on both a treaty and facultative basis, through reinsurance brokers, as well as directly with ceding companies primarily within the U.S. The International operation writes foreign property and casualty reinsurance through Everest Re's branches in Canada and Singapore and through offices in Brazil, Miami and New Jersey. The Bermuda operation provides reinsurance and insurance to worldwide property and casualty markets through brokers and directly with ceding companies from its Bermuda office and reinsurance to the United Kingdom and European markets through its UK branch and Ireland Re. The Insurance operation writes property and casualty insurance directly and through general agents, brokers and surplus lines brokers within the U.S. and Canada. The Mt. Logan Re segment represents business written for the segregated accounts of Mt. Logan Re, which were formed on July 1, 2013. The Mt. Logan Re business represents a diversified set of catastrophe exposures, diversified by risk/peril and across different geographical regions globally.
Incurred losses and LAE increased by 0.2% to $749.9 million in 2015 compared to $748.2 million in 2014, primarily due to the increase in current year attritional losses of $11.8 million, mainly related to $29.7 million of losses from the explosion at the Chinese port of Tianjin, partially offset by the decline in premiums earned. This increase in current year attritional reserves was mostly offset by $11.0 million of favorable prior years' development in 2015 compared to 2014 mainly related to Latin American and Canadian business. The $70.5 million of current year catastrophe losses in 2015 were due to the 2015 Chilean earthquake ($34.8 million), the Northern Chile storms ($19.5 million) and the New South Wales storms ($16.2 million). The $71.1 million of current year catastrophe losses in 2014 were due to the 2014 Chilean earthquake ($20.7 million), Japan snowstorm ($20.0 million), Hurricane Odile ($15.4 million) and the Brisbane hailstorm ($14.9 million).
Our principal investment objectives are to ensure funds are available to meet our insurance and reinsurance obligations and to maximize after-tax investment income while maintaining a high quality diversified investment portfolio. Considering these objectives, we view our investment portfolio as having two components: 1) the investments needed to satisfy outstanding liabilities (our core fixed maturities portfolio) and 2) investments funded by our shareholders' equity.
Our financial strength ratings as determined by A.M. Best, Standard & Poor's and Moody's are important as they provide our customers and investors with an independent assessment of our financial strength using a rating scale that provides for relative comparisons. We continue to possess significant financial flexibility and access to debt and equity markets as a result of our financial strength, as evidenced by the financial strength ratings as assigned by independent rating agencies. See also Item 1, Business, Financial Strength Ratings.
Liquidity. Our liquidity requirements are generally met from positive cash flow from operations. Positive cash flow results from reinsurance and insurance premiums being collected prior to disbursements for claims, which disbursements generally take place over an extended period after the collection of premiums, sometimes a period of many years. Collected premiums are generally invested, prior to their use in such disbursements, and investment income provides additional funding for loss payments. Our net cash flows from operating activities were $1,308.4 million, $1,313.8 million and $1,098.3 million for the years ended December 31, 2015, 2014 and 2013, respectively. Additionally, these cash flows reflected net tax payments of $164.9 million, $153.5 million and $69.3 million for years ended December 31, 2015, 2014 and 2013, respectively, and net catastrophe loss payments of $171.1 million, $320.0 million and $490.7 million for the years ended December 31, 2015, 2014 and 2013, respectively.
The Everest International Credit Facility requires Group to maintain a debt to capital ratio of not greater than 0.35 to 1 and to maintain a minimum net worth. Minimum net worth is an amount equal to the sum of $5,215.8 million (70% of consolidated net worth as of December 31, 2014), plus 25% of consolidated net income for each of Group's fiscal quarters, for which statements are available ending on or after January 1, 2015 and for which net income is positive, plus 25% of any increase in consolidated net worth of Group during such period attributable to the issuance of ordinary and preferred shares, which at December 31, 2015, was $5,469.0 million. As of December 31, 2015, the Company was in compliance with all Everest International Credit Facility requirements.