As a group, the largest mortgage lender-servicers in the business continued to expand market share in 2005, but some firms grew a lot more than others. Overall, the U.S. residential mortgage market grew at a robust 14.2 percent rate last year, as rising house prices and consumer willingness to cash out built-up home equity helped spur mortgage borrowing. An estimated $9.152 trillion of single-family mortgages were outstanding at the end of last year, an increase… [One data table included]