The average monthly premium for Medicare Advantage (MA) enrollees will drop about 4 percent, or $1.19, to $31.40, according to a new estimate released by CMS.

Additionally, CMS predicted 18.5 million more people will enroll in a MA plan next year, representing 32 percent of all Medicare beneficiaries.

“Medicare Advantage and the prescription drug benefit continue to be a great option for seniors and people living with disabilities,” CMS Acting Administraor Andy Slavitt. “Medicare enrollees will continue to have access to predictable premiums and high quality care.” 

The CMS release credited the enrollment gains and relatively stable premiums to the Affordable Care Act (ACA). Since the ACA was enacted, the average monthly MA premium has fallen by 13 percent, enrollment has increased by 60 percent, and its share of the Medicare market has increased from 2010, when only 24 percent of beneficiaries were covered by a MA plan.

Other studies have said the increased popularity of MA coverage has eased the transition into value-based care, with Harvard University researchers finding counties with greater MA penetration saw a significant decrease in fee-for-service Medicare spending.

Stable premiums may also explain a recent survey which found 78 percent of MA enrollees don’t switch plans from year-to-year.

The next open enrollment period for Medicare and prescription drug benefits.