www.thinkprogress.org/climate/2014/01/02/3110731/california-rooftop-solar-2013/
"2013 was a banner year for clean energy and the U.S. solar industry was no exception. California, the nation’s solar standout, more than doubled its rooftop solar installations last year from 1,000 megawatts (MW) to 2,000 MW. To put this number in perspective, writes Bernadette Del Chiaro of the California Solar Energy Industries Association, it took California over 30 years to build the first 1,000 MW of rooftop solar."
