The surge of signups in March and April could reflect people who waited until the March 31 deadline and ultimately only enrolled to avoid financial penalties on 2014 federal taxes for those who failed to obtain insurance.
The U.S. Department of Health Services said a total of 139,815 Wisconsin residents selected a plan between Oct. 1 and March 31. The figure also included those who signed up during a special enrollment period that ended April 19, which was for those whose applications were still pending on March 31 or who faced special circumstances such as a change of job or family status.
There had been 71,443 signups in the six months through March 1, which means 68,372 people signed up in the last seven weeks. The federal government had projected that 79,000 Wisconsin residents would sign up by March 31.
Wisconsin's enrollees were mostly white and generally older. The most popular coverage option remained the silver plan, which covers about 70 percent of medical costs, according to the government data.
Republican Gov. Scott Walker had declined to expand Medicaid as allowed under President Barack Obama's health care law. Instead he took a path that resulted in about 77,000 people losing state BadgerCare coverage while a roughly similar number of childless adults were brought into the program.
Walker's spokeswoman referred questions to the state insurance commissioner's office. J.P. Wieske, a spokesman for the insurance office, said he didn't want to comment until officials there had a chance to finish collecting their own data and analyzing the federal numbers.
Democratic Sen. Tammy Baldwin released a statement touting the signup numbers and challenging Walker to reveal how many of the 77,000 individuals were able to enroll successfully in the online exchanges.
"We should be doing everything we can to provide people with health coverage, not creating more people without health insurance," she said.
Wisconsin's enrollment numbers showed improvement in one area that had given health officials concern. To keep insurance costs down, insurers need to balance older and sick customers with younger and healthier people who don't use their coverage as much, and the latest numbers suggested that was happening.
As of March 1, 41 percent of enrollees were between the ages of 55 and 64. According to Thursday's numbers, 32 percent are in that category. Another 26 percent are between the ages of 18 and 34, below the national average of 28 percent.
The government data also show that 55 percent of enrollees are female, and 72 percent of the people who signed up chose the silver plan.
Thursday's report also marked the first time the government released signups by ethnicity. Nearly a quarter of enrollees declined to reveal their ethnicity but of those who did, 86 percent were white and 6 percent black. Asians and Latinos each comprised 3 percent.
The latest report didn't include information on how many of the newly enrolled have actually paid their insurance premiums. With grace periods for enrolling extending into mid-April, many who have signed up weren't obligated to pay until this week.
The next enrollment period for private health insurance coverage for 2015 is scheduled to run Nov. 15 through Feb. 15.