Year current US$ 1972 1136032.48536964 1973 1551445.57823129 1974 2344032.09628887 1975 2028799.581097 1976 2169497.73921545 1977 2459636.28298958 1978 2796841.0209454 1979 3991108.54503464 1980 6842299.28127291 1981 7688648.68105792 1982 7407853.36483161 1983 6914481.81578389 1984 6867896.85652755 1985 6338171.46483558 1986 5561945.03435826 1987 5748260.78966787 1988 6507949.02356113 1989 6352102.62087944 1990 8017895.84920208 1991 8303443.71592749 1992 9926572.76132818 1993 11370662.8034312 1994 15319640.5082275 1995 17724378.1345415 1996 19288242.0306612 1997 19846404.4716854 1998 17226509.142096 1999 19124476.1528014 2000 17824055.2551518 2001 18502902.8529768 2002 16084067.6345093 2003 20607510.4864713 2004 24467487.7162057 2005 30121630.0395654 2006 34161240.2658195 2007 38973008.4984318 2008 54756511.4676235 2009 73920569.3382992 2010 84910049.8927398 2011 98410169.1466112 2012 112128025.938112 2013 128199029.50932 2014 131238039.816686 2015 127600523.613024 2016 132861618.960268 2017 143152730.917666 2018 158532254.425653 2019 159294909.058653 2020 156262099.542212 2021 163954212.90893