Keywords: The Number of States Where the Enrollment Share for the Top Three Insurers Was at Least 80 Percent, by Market Segment 2010-2013.jpg U S GAO report http //www gao gov/products/GAO-15-101R www gao gov/products/GAO-15-101R Private Health Insurance Concentration of Enrollees among Individual Small Group and Large Group Insurers from 2010 through 2013 http //www 5ptsinsurance in 5 PTS insurance Note We measured the enrollment share of the three largest insurers using covered life-years which represent the average number of lives insured including dependents on a pre-specified day over the 12 months in the reporting year a We excluded data from California from all years because the National Association of Insurance Commissioners' 2010 data for this state did not include all insurers 2014-12-05 https //www flickr com/photos/usgao/15926595386/ U S Government Accountability Office other versions PD-USGov Government Accountability Office |