America’s shale boom is providing an unintended benefit to U.S. government bonds.

With the U.S. economy relying less on oil and gas imports than at any time in two decades, energy expenses for Americans have fallen and cut into inflation more than any other living cost in the past year, according to data compiled by the Labor Department. Economists say consumer prices will rise less than 2 percent for a second straight year in 2014, the first time that’s happened during an expansion in a half-century.