New York (CNN) It will cost a little less to buy Obamacare coverage in 2019.

The average premium for the benchmark silver plan will decline by 1.5%, the Centers for Medicare & Medicaid Services said Thursday.

It's the first time average premiums have fallen since the Affordable Care Act exchanges opened in 2014 — but the decline comes after a 37% spike for this year's benchmark silver plan.

Americans who buy those plans will save $6 a month over this year's rate, on average, but will still be paying $105 more a month than in 2017.

Premiums vary across the 39 states that use the federal exchange. The biggest drop will be in Tennessee, where premiums will fall by more than 26%.

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