Georgia employers’ health care costs are lower than the national average, a recent survey has found. And the survey — done by New York-based Mercer, the world’s largest human resources consulting company — finds that employers in the Peach State offer what are called “consumer-driven health plans’’ at a greater rate than their national counterparts. The Mercer survey, released last week, says that the 52 Georgia employers surveyed saw their health care premiums rise by an average of 2.6 percent in 2017, the same as the national trend.