Average loan-to-value ratios and debt-to-income ratios on loans securitized by Fannie Mae and Freddie Mac were slightly lower – and credit scores edged slightly higher – during the fourth quarter, according to a new Inside Mortgage Trends analysis. The average LTV ratio edged down from 78.53 percent in the third quarter to 77.54 percent in the final three months of 2012. The average DTI ratio declined slightly, from 31.92 percent to 31.88 percent, while the average ... [Includes one data chart]