Below are some of the key assumptions used in the income approach model for estimating broadcasting licenses fair values for the annual impairment assessment as of October 1, 2013, and interim impairment assessments for the quarters ended March 31, 2014 and 2013. Radio Broadcasting | | March 31, | | | October 1, | | | March 31, | | Licenses | | 2014 (a) | | | 2013 | | | 2013 (a) | | | | | | | | | | | | | | | Pre-tax impairment charge (in millions) | | $ | — | | | $ | — | | | $ | 1.4 | | | | | | | | | | | | | | | Discount Rate | | | 10.0 | % | | | 10.0 | % | | | 10.0 | % | Year 1 Market Revenue Growth Rate Range | | | 1.0 | % | | | 0.0% – 2.0 | % | | | 1.0 | % | Long-term Market Revenue Growth Rate Range (Years 6 – 10) | | | 1.5 | % | | | 1.0% – 2.0 | % | | | 1.5 | % | Mature Market Share Range | | | 8.6 | % | | | 6.4% – 26.9 | % | | | 8.6 | % | Operating Profit Margin Range | | | 33.6 | % | | | 30.8% – 47.8 | % | | | 31.4 | % | (a) | Reflects changes only to the key assumptions used in the interim testing for certain units of accounting. | |