Year US Dollars adjusted for inflation) 1977 1000000 1979 19000000 1980 6000000 1982 2000000 1983 15000000 1986 10000000 1988 1000000 1990 0 2005 15000000 2011 7000000 2013 10000000 2014 16000000 2016 8000000 2018 10000000