The selected consolidated financial data shown below has been derived from the Consolidated Financial Statements. All information contained herein should be read in conjunction with the Consolidated Financial Statements and related Notes, the Schedules, Exhibit 12 and
Our organization is focused on generating consistent, industry-leading combined ratios. We concentrate our insurance writings in selected specialty lines of business in which we believe we can achieve meaningful underwriting profit. We rely on experienced underwriting personnel working within defined and monitored limits, as well as our access to and expertise in the reinsurance marketplace, to limit or reduce risk. By focusing on underwriting profitability, we are able to accomplish our primary objectives of maximizing net earnings and growing book value per share.
Our net loss ratio is the percentage of our loss and loss adjustment expense excluding internal claims department costs divided by our net earned premium in each year. In evaluating our businesses, we consider internal claims department costs to be operating expenses and, thus, exclude them from the calculation of our net loss ratios and include them in the calculation of our expense ratios. The reclassification discussed in the previous paragraph had no impact on our segment reporting, which reflects the way in which our management viewed and evaluated our segment results.
Our income taxes are due to U.S. Federal, state, local and foreign jurisdictions. Our effective income tax rate was 30.7% for 2014, compared to 28.9% for 2013 and 29.4% for 2012. Fluctuations in our effective tax rate are due to the relationship of pretax income and tax-exempt investment income. In 2014, our pretax income was substantially higher and our tax-exempt investment income was flat compared to 2013. The lower effective rate in 2013 related to an increased benefit from tax-exempt investment income in that year.
In our Liability line of business, we experienced lower losses in 2014, compared to 2013, due to higher favorable development in the professional lines, which include our E&O and employment practices liability products. In 2014, we recognized favorable development in our professional lines based on better than expected actuarially-indicated results since our 2013 annual reserve review, primarily for underwriting years 2012 and prior. In 2013, we recognized favorable development for underwriting years 2010 - 2011 due to better than expected actuarially-indicated results. In 2012, we recognized adverse development related to underwriting years 2005 - 2010.
The majority of the favorable loss development in Other relates to the run off of an assumed quota share contract for business that we wrote from 2003 - 2008. We recognized $5.0 million in 2014, $17.0 million in 2013 and $5.6 million in 2012, due to continued better than expected results since the prior annual review. This assumed quota share contract is no longer earning premium, resulting in low or negative loss ratios in total for the Other line.
The segment had net favorable loss development of $22.6 million in 2014, $37.9 million in 2013 and $25.4 million in 2012. Each of our annual reserve reviews, which we conducted in the fourth quarter, indicated that actual loss experience was better than the actuarial expectations in the prior year reserve review. As a result, we recognized favorable loss development as follows: 1) 2014 - $20.3 million for surety and $2.3 million for credit, 2) 2013 - $20.6 million for surety and $17.3 million for credit and 3) 2012 - $18.0 million for surety and $7.4 million for credit.
The average duration of claims in many of our lines of business is relatively short. However, we write D&O, E&O and casualty insurance, all of which have a longer claims duration than our other products. We consider these different claims payment patterns in determining the duration of our investment portfolio. The weighted-average duration of all claims was approximately 2.3 years, 2.1 years and 2.2 years at December 31, 2014, 2013 and 2012, respectively. The weighted-average duration of our fixed maturity securities was 4.7 years, 5.1 years and 4.7 years at the respective year-end. The longer duration of our fixed maturity securities reflects the effects of the investment of our capital.