Wal-Mart Stores Inc. says more of its workers are enrolled in the retail giant's health insurance plan in 2010 than last year, but the share of its employees who are insured at all has declined.

Wal-Mart, the world's largest private employer with more than 2 million workers, says 54 percent of its employees now have coverage, which reaches about 1.2 million people including family members. The figure is up from 52 percent last fall, according to data provided to The Associated Press by the company.

The number of Wal-Mart employees with health coverage — provided by either Wal-Mart or another source — dropped from 94 percent last year to 87 percent.

Wal-Mart said 43,000 of its workers receive health coverage through a state assistance program, up from 36,000 last year.

Union-backed groups have criticized Wal-Mart for the number of workers that receive health assistance from public programs and for not enrolling more workers in its own plan. The company has made a number of changes over the years, including making improvements to its health coverage.

Last summer amid the debate over overhauling the nation's health care system, Wal-Mart came out in favor of a proposal that would require large companies to provide health insurance for their workers. Wal-Mart was joined in the endorsement by one of its persistent critics, the Service Employees International Union.

Wal-Mart spokesman David Tovar said the company is just starting to examine the numbers to try to find more specific causes for the changes. The recession is likely the general reason for the changes, but Tovar said the numbers point to a bigger problem.

"We believe this is just one more indicator that our nation's current health care system is not sustainable," Tovar said.