The average monthly premium for individuals purchasing a plan from increased by 105% from 2013 to 2017, according to the Department of Health & Human Services.

In the 39 states that use, the average monthly exchange plan premium went from $232 in 2013 to $476 in 2017, an increase of $244 (105%), the HHS Office of the Assistant Secretary for Planning and Evaluation (ASPE) reported.

All 39 states experienced an increase in the cost of an average premium, but there was considerable variation in the size. Alabama had the largest percent increase at 223%, but Alaska had the largest absolute increase – $697 – to go with the second-largest percent increase – 203%. Oklahoma, where the average premium jumped 201%, was third, the ASPE said.

The state with the smallest change, both in terms of dollars and percents, was New Jersey, which had an increase of $51 (12%) over the 4-year period. The only other states with less than a 50% increase were New Hampshire at 32% and North Dakota at 44%, the report showed.

“States with benefit mandates similar to those required in the [Affordable Care Act] in effect before 2014 had smaller premium increases between 2013 and 2017,” the ASPE noted.

One limitation to the analysis is the change among those enrolling from 2013 to 2017. “Older and less healthy people are a larger share of the individual market risk pool now than in 2013. The changing mix of enrollees and adverse selection pressure has likely been a significant cause of the large average premium increases,” the ASPE said.