Year kWh 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 0 1991 0 1992 0 1993 0 1994 0 1995 0 1996 0 1997 1000000 1998 27000000 1999 21000000 2000 6000000 2001 3000000 2002 2000000 2003 3000000 2004 3000000 2005 5000000 2006 7000000 2007 14000000 2008 21000000 2009 33000000 2010 27000000 2011 44000000 2012 218000000 2013 387000000 2014 521000000 2015 782000000