The U.S. economy added 257,000 jobs in January, the Bureau of Labor Statistics reported Friday. The report also included revisions to job-creation figures for November and December 2014, adding 147,000 more jobs. That brings job-creation in the past three months to over 1 million – the strongest since 1997, according to Capital Economics research.

The unemployment rate increased marginally (by 0.1 percent) to 5.7 percent in January, as 703,000 additional adults were counted in the labor force.

The report does not provide detailed information about those entering or returning to the labor force. Elise Gould of the Economic Policy Institute says that by age distribution they appear to mirror the active workforce as a whole: 72 percent are prime-age working adults, age 25 to 54. “The uptick [in the labor force] may be disproportionately more Hispanic workers and white workers, and fewer black workers,” Gould says.

Job creation in the past several months has been broad-based, according to Gary Burtless, a labor economist at the Brookings Institution. New workers hold lower-paid retail and restaurant jobs as well as higher-paid positions in finance, professional services and IT. Traditional middle-income-tier jobs are also filling out a bit, he says.

“The construction industry has picked up employment gains,” says Burtless, “and manufacturing has been adding steadily to payrolls for quite a while.” But he points out that neither of these goods-producing employment sectors is as robust as before the recession.