Year US Dollars adjusted for inflation) 1971 10000000 1972 2000000 1973 76000000 1974 44000000 1975 39000000 1976 70000000 1977 62000000 1978 45000000 1979 1000000 1980 55000000 1981 62000000 1982 128000000 1983 109000000 1984 59000000 1985 81000000 1986 4000000 1987 1000000 1988 242000000 1989 302000000 1990 188000000 1991 79000000 1992 113000000 1993 47000000 1994 61000000 1995 119000000 1996 7000000 1997 26000000 1998 1000000 1999 186000000 2000 203000000 2001 279000000 2002 33000000 2003 8000000 2004 32000000 2005 10000000 2006 221000000 2007 88000000 2008 12000000 2010 36000000 2011 117000000 2012 184000000 2013 650000000 2014 203000000 2015 636000000 2016 449000000 2017 331000000 2018 155000000 2019 714000000 2020 59000000 2021 73000000 2022 184000000