Last year in Michigan more workers became a part of a labor union. Studies show there were about 629,000 workers in the state who were in a union in 2012. In 2013 membership rose to about 633,000, or a jump of about 4,000. Analysts are saying the increase can be attributed to an improving economy. They say in Michigan that's evidenced by the rebound of the auto industry. Last year in Michigan 16.9% of workers were in a union. Nationally, 11.3% were. (Pictured: United Auto Workers President Bob King)