Illinois' unemployment rate fell to 9.1 percent in May, according to preliminary data released Thursday by the U.S. Bureau of Labor Statistics and the Illinois Department of Employment Security.

Businesses in the state added 11,800 private sector jobs.

In April, the state's jobless rate stood at 9.3 percent, according to IDES. It was 8.9 percent in May 2012.

"Growth in construction is particularly encouraging following a cold and wet spring," IDES Director Jay Rowell said in a statement. "This year also illustrates the volatile nature of the unemployment rate. Up in January and February, unchanged in March, and then down again in April and May. This trend likely will continue as national and global events push consumer confidence."

Illinois has added more than 227,600 private sector jobs since January 2010 when job growth returned following nearly two years of consecutive monthly declines.

The U.S. jobless rate for May was 7.6 percent.