Indiana added 12,000 private-sector jobs in December, but its unemployment rate held steady at 9 percent as a huge wave of Hoosiers entered the labor force.

The Indiana Department of Workforce Development reported Tuesday morning that 17,200 Hoosiers began looking for jobs last month, the highest total in 35 years.

“December was one of the best months for job creation in over a decade,” Mark W. Everson, commissioner of the Department of Workforce Development, said in a prepared statement.

Nationally, 37 states saw declines in their unemployment rates, while 10 held steady and three saw increases, according to the U.S. Bureau of Labor Statistics.

Statewide non-farm employment totaled 2.81 million on a seasonally adjusted basis, the highest level since March 2009. A total of 275,038 Hoosiers remain out of work, down from 283,803 in December 2010.

Sectors showing big job gains in December were professional and business services, which added 4,800 jobs, and manufacturing and construction, with each adding 3,600 jobs. A big declining sector was leisure and hospitality, which lost 1,700 jobs in December.

Indiana’s unemployment rate remains higher than the national rate of 8.5 percent. But Workforce Development officials noted that since July, a larger percentage of Hoosiers have entered the labor force—which means they are either getting a job or looking for one— than Americans as a whole.

A year ago, Indiana’s unemployment rate was 9.5 percent.

In the Indianapolis metropolitan area, the non-seasonally adjusted jobless rate was 8.2 percent in December, down from 8.4 percent in December 2010. In all, 73,329 people are out of work in the Indianapolis area.

Comparisons of metro areas are more accurately made using the same months in prior years because the government does not adjust the figures for factory furloughs and other seasonal fluctuations.