DETROIT (WTVB) - There’s at least one indicator that the Michigan economy is gaining steam, or at least it was for awhile this summer. Comerica Bank's latest Michigan Economic Activity Index shows July rising to levels not seen since November 2002.  Chief Economist Robert Dye says job creation picked up, housing markets are improving and the August vehicle sales figures picked up to rate of 14-point-five million units for the year. Comerica's Michigan Economic Activity Index bottomed out in the summer of 2009, and the state has been steadily improving since then.