American Market & Business News reports Drew Industries, manufacturer of components for the manufactured housing and RV Industries, announced their quarterly revenue gained 15.80 percent for the first quarter 2011 over the same period 2010.  The company said earnings for 2010 were .30 cents per share, as opposed to .42 cents per share for first quarter 2011.  For the year ending December 31, 2009, the RV division accounted for 79 percent of net sales and the MH division for 21 percent.  As of the same date, Drew had 24 manufacturing operations in 12 states.