"Federally-facilitated exchange states reenrolled 78 percent of their 2014 enrollees in 2015, on average. In state-run exchange states, that percentage drops to 69 percent of 2014 enrollees. California, the state with the highest enrollment in 2014, only retained 65 percent of their 2014 enrollees. It is unclear why state-based exchanges saw higher year-over-year attrition among their enrollees. One possibility is that state exchanges had more enrollees who over-reported income in 2014."