Despite recovering house values in most markets, insufficient collateral remained the biggest obstacle for consumers trying to get mortgage financing in 2012, according to a new Inside Mortgage Trends analysis of Home Mortgage Disclosure Act data. In virtually every category of the market, loan applicants were more successful in getting approved for a mortgage last year than they were back in 2011, the HMDA data show. Some 15.5 percent of loan applicants were turned down last year ... [Includes one data chart]