Sales of U.S.-backed mortgage bonds have soared to a three-year high as steps by the Federal Reserve Board and Obama administration to make home ownership more affordable propelled a 34 percent jump in refinancing, Bloomberg reported.

Issuance of securities guaranteed by government-supported Fannie Mae and Freddie Mac or U.S.-owned Ginnie Mae has climbed to $1.72 trillion, compared with $1.22 trillion last year and $1.73 trillion in 2009, according to data compiled by Bloomberg.

With weekly rates on 30-year home loans falling to record lows eight times since July, the first increase since 2009 in refinancing has driven total lending to almost $1.8 trillion this year, double a forecast from the Mortgage Bankers Association in October 2011. Read more.