The average cost of healthcare coverage per employee is expected to cross the $10,000 mark for the first time in 2012, according to an analysis by Aon Hewitt, a division of Aon Corp.

The total average healthcare premium per employee for large companies is expected to be $10,475 in 2012, up 7 percent from $9,792 in 2011.

Several factors are driving the increase, according to Aon Hewitt. One factor cited by the firm is slower hiring, which has resulted in a slightly older workforce that is more prone to costly medical conditions.

Aon Hewitt’s data comes from a database that captures healthcare costs and benefit data for 371 large U.S. employers.