Big U.S. employers’ annual, per-employee health care spending will increase an average of about 7% in 2010, to more than $10,000.

Consultants in the Stamford, Conn., office of Towers Perrin Forster & Crosby Inc. have based that forecast on a survey of about 300 large employers.

The average employee health benefits contribution will increase by 10% at the participating employers, to about $2,000, the consultants predict.

Participating employers will be paying an average of about $5,124 per year for employee-only coverage and $15,084 per year for family coverage, the consultants report.

The percentage of employers offering an account-based health plan, such as a plan incorporating a health savings account or a health reimbursement arrangement, has increased to 60% at the participating employers, from 20% 5 years ago.

Current health reform proposals could accelerate adoption of ABHPs, because the plans have a lower actuarial value than traditional health plans, and offering them would help employers delay reaching the threshold for the proposed “Cadillac plan” excise tax, the Towers Perrin consultants write.