More of the nation's smallest businesses are providing health-care coverage, though many have started offloading rising costs onto employees, a recent survey finds.

In a survey of nearly 4,000 micro-business owners nationwide, 67 percent said they offered personal health insurance coverage last year, up from 54.9 percent in 2005, according to the National Association for the Self-Employed.

The gains came despite a 14.7 percent increase in costs, with one in 10 survey respondents saying they now spend about a quarter of annual revenue on health insurance.

The largest increase in employer-provided health-care coverage last year came from businesses with less than $50,000 in gross annual sales. Overall, the survey found businesses with lower revenue tended to devote a larger portion towards health care, compared to wealthier businesses.

To cope many owners are getting employees to pay a bigger share of their health insurance premiums, with the average employee contribution rising to 87 percent from 64.5 percent in 2005.

"The baker, the house painter, and the 20 million other micro-businesses in the United States already are struggling to survive in this economy," Kristie Darien, the Washington-based group's executive director, said in a statement. "These businesses could be further threatened if we cannot find a way to make insurance more affordable," she said.