The Centers for Medicare and Medicaid Services said Friday after markets closed that it expects costs per person for Medicare Advantage plans to fall more than 2 percent in 2014. The government uses this figure as a benchmark to determine payments for these privately run versions of the government's Medicare program that covers the elderly and disabled people.

Medicare Advantage plans are offered by health insurers and subsidized by the government. They offer basic Medicare coverage topped with extras like vision or dental coverage or premiums lower than standard Medicare rates. UnitedHealth and Humana are the two largest Medicare Advantage providers.

Insurers offer hundreds of different Medicare Advantage plans around the country, all with their own sets of variables like different deductibles, premiums and co-insurance.