Government data released Wednesday show sign-ups for Affordable Care Act health plans are running more than 45 percent ahead of last year's pace as people rush to meet a shorter deadline.
The numbers from the Centers for Medicare and Medicaid Services come as Republican senators are pushing to pay for tax cuts by repealing Obamacare's requirement to carry coverage.
The new figures show that nearly 1.5 million consumers picked a plan through Nov. 11, compared to just more than 1 million from Nov. 1 to Nov. 12 last year. The share of new customers for 2018 coverage stayed at about 23 percent.
The data cover 39 states served by the HealthCare.gov website.
The Obama-era law offers subsidized private insurance for people who don't get coverage on the job. Sign-ups this year are being closely watched because of efforts by the Trump administration and the Republican-controlled Congress to do away with the law.
The Congressional Budget Office has estimated that 13 million more people would be uninsured by 2027 if Congress repeals the requirement that people buy insurance.
Sign-up season ends Dec. 15, giving consumers just 45 days to sign up. Previous sign-up periods lasted 92 days.