Blood donations in the U.S. are falling by about 1 percent a year, while demand for blood is growing by the same amount. The trend is serious enough to alarm federal officials, the Orlando Sentinel reports.

Surgeon General David Satcher has a committee searching for ways to get more people to donate blood more often. Committee ideas include incentives such as giving donors time off from work or small rewards like T-shirts, the newspaper reports.

"We operate on a very thin margin of safety for the blood supply, and if that trend continues it would put us in a year-round shortage in a few years," said Dr. Arthur Caplan of the University of Pennsylvania, who heads a federal committee on blood issues.

The National Blood Data Resource Center predicts the shortage will come even sooner. Next year, Americans will donate just under 11.7 million units of blood, but hospitals will need 11.9 million units, the committee predicts.

Pushing donations down even further, the government is about to ban Americans from giving blood if they have traveled in Great Britain for six months or more since Britain's mad cow disease epidemic began in 1980. Experts want the precaution measure even though there's no proof the disease spreads through human blood, the paper reports.

This restriction is expected to decrease the blood supply by another 2.2 percent a year.

About 60 percent of Americans are estimated to be eligible donors, but only 5 percent donate, the center reports.

"There are people who would donate at least twice as much if they knew they were needed," said Satcher.