A major insurer on Wednesday reported a huge drop in the number of Obamacare customers it has.

Humana reported in its latest fourth quarter 2016 earnings Wednesday that total enrollment in the individual market, which includes Obamacare's exchanges, declined by 69 percent in January 2017 compared to the month before.

The company said on Dec. 31 it had about 450,800 in the individual market, which includes Obamacare's marketplaces. However, in January 2017 membership dropped by 69 percent to 204,000.

Humana lowered its presence in Obamacare from offering plans in 15 states to just 11 states in 2017 due to mounting financial losses, but the company said the decline isn't just due to pulling out of four states. The decline reflects "membership declines during the ongoing open enrollment period for healthcare exchanges" as well.

Open enrollment for Obamacare ended on Jan. 31. Full totals aren't available yet, but healthcare.gov reported lower enrollment of 9.2 million compared to 9.6 million for the 2016 open enrollment season.

Residents in 38 states and the District of Columbia use healthcare.gov to sign up for Obamacare. The total doesn't reflect the 12 state-run exchanges.

Overall, Humana reported losing $486 million in the fourth quarter of 2016.

Humana isn't the only insurer to reduce its Obamacare plans. Aetna and UnitedHealth both withdrew from a majority of its offerings for this year.