The unemployment rate for Americans with disabilities is edging up as less people in this population actively seek work, according to new data from the U.S. Department of Labor.  Figures released just before Labor Day show that the jobless rate for those with disabilities hit 11.3 percent in August, up slightly from 11.1 percent the month prior.  The shift appears to be due at least in part to more individuals with disabilities giving up on the job market altogether.