The average monthly premium for health insurance bought on healthcare.gov, the federal marketplace used by 38 states, rose to $408 in 2016, preliminary data show. Above, Martha Lucia sits with an insurance agent from Sunshine Life and Health Advisors as she picks an insurance plan available in the third year of the Affordable Care Act at a store setup in the Mall of the Americas Nov. 2, 2015 in Miami, Florida. Joe Raedle/Getty Images

The average premium for health insurance plans bought on Healthcare.gov, the federal marketplace created under the Affordable Care Act, also known as Obamacare, rose approximately 9 percent for 2016 plans, the Hill reported, based on comparisons of preliminary numbers released by the Department of Health and Human Services and data from 2015.

The average premium for a plan purchased on Healthcare.gov cost $408 a month, the Department of Health and Human Services said in a report issued Thursday, which it noted contained preliminary data that would be updated after the 2016 enrollment period closes Jan. 31. However, the actual amount paid by those who buy insurance on the federal platform, used by 38 states, is typically less, because 83 percent of them receive financial aid to offset the cost of health insurance.

Changes in Premiums for Obamacare Marketplace Plans From 2015 to 2016 | HealthGrove

The average amount of financial aid, typically in the form of advance tax credits, came to $294 for 2016 plans, the report said, bringing the final average monthly cost down to $113 per month.

In 2015, the average Obamacare premium, before subsidies, came to $374 per month, while the average subsidy amounted to $268 per month, according to the Department of Health and Human Services.

In its report, the administration said that more than 8.5 million people had signed up for new plans or renewed existing ones through Healthcare.gov between Nov. 1 and Dec. 26, 2015. Previous customers who actively shopped for new plans, instead of automatically enrolling in the same ones, tended to save an average of $43 per month, compared to those who didn't. Of the 3.6 million preexisting Obamacare customers who actively signed up again instead of allowing their plans to roll over automatically, 60 percent chose new plans.

The average monthly premium is only one indicator of healthcare accessibility and affordability. Co-pays, deductibles and doctor networks are other key factors that influence whether and how patients can get medical care when they need it.