The General Services Administration, which runs the government fleet, bought at least 14,584 hybrid vehicles in the past two fiscal years, or about 10 percent of 145,473 vehicles the agency purchased in that period, according to sales data obtained by Bloomberg under a Freedom of Information Act request.

In fiscal 2008, hybrids accounted for less than 1 percent of government purchases, the data show.

The government is boosting investment in a technology that has not won broad acceptance after more than a decade in the marketplace. Consumer purchases of hybrids are headed for their third consecutive yearly decline. Government agencies and businesses have said they also will purchase all-electric models being introduced by automakers, including GM.

“At some point, the reality is that for this technology to be accepted, it needs to be done without a government crutch,’’ said Jeff Schuster, director of forecasting at J.D. Power & Associates. “But without a huge gas-price increase or further government demand, the natural demand just isn’t to be there.’’

About 3,100 of the hybrids purchased by GSA were paid for out of $300 million the agency received from the 2009 economic stimulus package, said Sara Merriam, a spokeswoman. Another 5,600 were bought with proceeds from selling older cars in the government fleet. A majority of fiscal 2009 hybrid sales came after Obama took office.

“This is the beginning,’’ Merriam said. “Our main goal is to increase the fuel efficiency of the federal fleet. The other goal is to drive the market toward cleaner technologies.’’

The government paid an average of $5,281 less for its hybrid vehicles than sticker prices at a dealership, according to a comparison of GSA data with prices collected by Edmunds.com, a consumer website.

Global sales of hybrids, plug-in hybrids, and electric cars are projected to be 954,500 vehicles, or 2.2 percent of the 44.7 million passenger vehicles projected to be sold this year, J.D. Power said in an Oct. 27 report. That may rise to 5.2 million units in 2020.

“The lesson learned is that it isn’t easy to make these vehicles mainstream,’’ said Brett Smith, who specializes in alternative propulsion vehicles at the Center for Automotive Research in Ann Arbor, Mich. “They are still not near the point where they are cost-competitive in the market.’’

“It is good that the government leads by example,’’ said Dan Becker, director of the Washington-based Safe Climate Campaign. “It’s a positive sign that the government is stepping up to the plate.’’