Over 1 million people have already dropped their exchange insurance in 2018, a trend that's likely to worsen over the remainder of the year.

In February 2018, about 10.6 million people were enrolled in an Affordable Care Act (ACA) exchange plan, with about 87% using advance premium tax credits to subsidize their premiums. That's slightly more than the 10.3 million enrolled in February 2017, with 84% using tax subsidies, according to a report (PDF) by the Centers for Medicare & Medicaid Services (CMS). 

However, about 11.8 million people signed up for coverage in 2018, meaning 9%, or 1.1 million did not pay their initial premium and dropped from the plans. That's less than the nearly 15.5% who dropped in early 2017.

Participation is likely to continue to drop throughout the year. Only 8.9 million people remained in their plans by the end of 2017.

Additionally, in 2017, monthly enrollment fell by 20% among those without an advance premium tax credit, representing 85% of the enrollment loss for that year. 

RELATED: ACA exchange enrollment totals 11.8M in 2018, down 3.7% from last year

While the changes in enrollment may be light, several significant changes are scheduled for next year that will likely reduce participation in marketplace, including a zeroed-out individual mandate, and expansion of short-term and associated health plans. 

CMS Administrator Seema Verma has said the expansion of short-term plans would have a minimal impact on ACA exchanges, but the agency's actuary reported as many as 800,000 ACA enrollees could opt for short-term plans instead. 

The Trump administration, which has said it wants to wind down the ACA exchanges by 2020, was quick to pounce on the report. 

“As the Trump Administration took office, there were warning signs that we were dealing with a crisis in the individual health insurance market and Obamacare was failing its consumers," CMS Administrator Seema Verma said in a statement. "These reports show that the high price plans on the individual market are unaffordable and forcing unsubsidized middle-class consumers to drop coverage." 

The report comes as insurers are filing proposed rates for 2019. In some states, like Maryland, insurers have requested rate hikes as high as 91%. Average rate hikes in the District of Columbia, Washington and New York have also reached double digits. 

At the same time, Oscar Health announced it will offer exchange plans in three additional states, and expand offerings in Tennessee, Ohio and Texas.