The United Auto Workers strike at General Motors Co. is starting to take a toll on businesses throughout Michigan, creating a growing threat to the state’s already-slowing economy, the Wall Street Journal reported. Michigan’s economy faces the greatest exposure from a prolonged strike, because it has about 15 GM manufacturing facilities employing tens of thousands of workers, more than any other state. Lost earnings to workers will result in lower sales-tax and income-tax revenues for the state, and some local businesses near idled GM plants are already reporting lost sales. Michigan relies far more on the automotive industry for wage and salary income than the U.S. as a whole. The sector accounts for 7 percent of such income, compared with less than 2 percent nationally, according to Moody’s Investors Service.