The US Department of Energy reported in late September that the price of solar rooftop systems in the United States fell 12% to 19% in 2013. Another drop of 3% to 12% is expected in 2014 . . . .  The top 10 US wind companies and their market shares as of the end of Q2 2014 were NextEra 20.07%, Iberdrola Renewables 10.48%, EDP Renewables 7.07%, E.On 6.49%, Invenergy 5.74%,  NRG Energy 4.11%, EDF Renewable Energy 3.57%, Duke 3.48%, BP 3.09% and Enel 3.05%, according to Platts. The top 10 account for 67% of the market. There were 78 US wind companies making wholesale electricity sales.