About 95 percent of the company’s roughly 90,000 employees have benefits covered completely, Lou Gellos, a spokesman for Redmond, Washington-based Microsoft, said in an interview today. He said he didn’t know what portion employees will be asked to provide.

“The cost of health care has, over the years, increased dramatically,” Gellos said in an interview today. “The projections going forward have them going way up, and in order to be sustainable, some sort of evolution of our health benefit was necessary.”