Year current US$ 1960 12.353809917002017 1961 22.146234949984304 1962 16.374169172737 1963 19.284889139254584 1964 16.19121621272807 1965 20.398080751665542 1966 18.210707020814944 1967 19.205061590082707 1968 15.017754557385148 1969 23.545511492181543 1970 22.35802770575151 1971 20.538243684953414 1972 21.305797972936276 1973 24.533049021466056 1974 31.036238466097437 1975 37.14114332256113 1976 36.73862969436954 1977 40.55299024647988 1978 49.64127186534154 1979 32.70632157046384 1980 36.557356761916104 1981 36.01100238141057 1982 29.982807114232568 1983 28.592902894239817 1984 24.192362673798076 1985 21.45773462511497 1986 28.696504879596233 1987 34.82975503931968 1988 39.01824989977008 1989 33.899780806109355 1990 46.50935294191994 1991 41.1070432784924 1992 44.07704937829024 1993 27.090933520858066 1994 11.570422124686363 1995 8.11159586904129 1996 13.452025662379395 1997 20.42488630621374 1998 15.599638107618793 1999 25.891730479141692 2000 22.524297853004086 2001 36.63986938637003 2002 21.53139756186683 2003 29.593485512243223 2004 32.42156117276935 2005 35.45801006431016 2006 41.670013759023036 2007 31.058385377064187 2008 35.66071573457012 2009 46.17087560779624 2010 50.49535045497791 2011 83.86382345630575 2012 91.47082258437088 2013 63.24265594957888 2014 80.73359089629518 2015 42.90357127586434 2016 55.35156934766488 2017 68.73758055204922 2018 67.61059379524205 2019 81.25691029841774 2020 80.18107423170532 2021 89.17596624773117 2022 98.11254126700969