New eligibility requirements mandated by the Affordable Care Act (ACA) had very little impact on enrollment in employer-sponsored plans in 2015, health consultant Mercer reported. A survey of nearly 600 employers last month found there was virtually no change between 2014 and 2015 in the average percentage of all employees – full-time and part-time – enrolled in employer-sponsored health plans. While there was a 1.6 percent increase in the absolute number of employees enrolled, that was the result of a 2.2 percent increase in the size of the workforce, rather than the changes required by the ACA, Mercer said.