DALLAS, Feb. 27, 2014 /PRNewswire/ -- Comerica Bank's Michigan Economic Activity Index decreased in December, down 4.3 percentage points to a level of 127.1. December's reading is 55 points, or 76 percent, above the index cyclical low of 72.1. The index averaged 126 for all of 2013, 12 points above the index average for 2012. November's index reading was unchanged at 131.4. (Logo: http://photos.prnewswire.com/prnh/20010807/CMALOGO) "Our Michigan Index fell again in December after dipping in November. Some of the December drag may be attributable to the very bad winter weather that Michigan is still enduring. Payroll employment for the state was essentially unchanged from September through December of last year. Also, sales tax data was soft at the end of last year," said Robert Dye, Chief Economist at Comerica Bank. "Auto sales nationwide were hurt by the severe winter weather, pushing light vehicle sales down to a 15.2 million unit rate in January. Fortunately, it does look like auto sales in February will improve, and this is supportive of the increase in assembly line activity that we saw through 2013." The Michigan Economic Activity Index consists of seven variables, as follows: nonfarm payrolls, exports, sales tax revenues, hotel occupancy rates, continuing claims for unemployment insurance, building permits, and motor vehicle production. All data are seasonally adjusted, as necessary, and indexed to a base year of 2008. Nominal values have been converted to constant dollar values. Index levels are expressed in terms of three-month moving averages. Comerica Bank, with 214 banking centers in Michigan, is a subsidiary of Comerica Incorporated (NYSE: CMA), a financial services company headquartered in Dallas, Texas, and strategically aligned by three business segments: The Business Bank, The Retail Bank, and Wealth Management. Comerica focuses on relationships, and helping people and businesses be successful. In addition to Michigan and Texas, Comerica Bank locations can be found in Arizona, California, and Florida, with select businesses operating in several other states, as well as in Canada and Mexico. To find Comerica on Facebook, please visit www.facebook.com/ComericaCares. To subscribe to our publications or for questions, contact us at ComericaEcon@comerica.com. Archives are available at http://www.comerica.com/economics. Follow us on Twitter: @Comerica_Econ.