Year current US$ 1960 3.5927028467380984 1961 6.174790379278862 1962 8.457250592674127 1963 12.190395861986746 1964 9.4007356467833 1965 8.594315245879503 1966 7.145465380655938 1967 6.97511589715864 1968 9.5733918166328 1969 7.416244686978239 1970 6.4941112906261935 1971 6.8298158909814015 1972 9.954516542750412 1973 4.914072105815108 1974 10.770349228573737 1975 9.243773816539353 1976 10.458864526547325 1977 12.708995715061455 1978 20.947362945139673 1979 22.027028798593857 1980 24.04774864705806 1981 21.315063000397917 1982 18.277056135432485 1983 25.008905523332444 1984 20.92315193087602 1985 24.930977358262535 1986 38.528159116528975 1987 42.34373669756677 1988 60.046395387731636 1989 69.6892088040399 1990 68.35213475631049 1991 65.95130245004293 1992 88.83591998890488 1993 72.45288516123331 1994 70.0701137350606 1995 86.56794207671226 1996 95.13894850317152 1997 77.20808482522271 1998 66.29598020502145 1999 61.59578084820357 2000 49.58652907462675 2001 77.28716325759689 2002 67.44839266032842 2003 84.19986500318447 2004 76.67519322543632 2005 57.89245415491104 2006 84.63046170507519 2007 43.73528508468439 2008 57.12106698944466 2009 57.64717127872706 2010 54.80340630065038 2011 52.51606884861372 2012 62.60538695698893 2013 65.37067610788489 2014 61.78994236766921 2015 71.3529244869263 2016 61.84045832893102 2017 83.00093866586988 2018 62.79624026535825 2019 60.13255247117284 2020 28.398575791841886 2021 41.957132507465474 2022 27.332049969409884