Year current US$ 1967 241.13518970437926 1968 270.59360351477 1969 299.07901841805443 1970 319.04548024254876 1971 344.92909333316635 1972 422.4813573347338 1973 511.31175178586705 1974 701.9714136764301 1975 921.541654773438 1976 1141.0446109024497 1977 1186.0688830569518 1978 1270.7377425856591 1979 1487.3291063661645 1980 1675.2601156762182 1981 1716.8377662135658 1982 1838.6561135467975 1983 1798.5897048139814 1984 1777.8254729724154 1985 1910.1034077744212 1986 1990.0064193149703 1987 2050.9794765294932 1988 1960.2229104512107 1989 1793.7987101476795 1990 2007.2634630288 1991 1205.7401929492958 1992 1226.8326031662887 1993 1198.5475127014142 1994 1245.1736108911944 1995 1239.382712106807 1996 1352.8870911202525 1997 1438.2724789356016 1998 1470.9753372898006 1999 1507.939044414864 2000 1595.512713878758 2001 1640.0324922666864 2002 1599.0048471882296 2003 1661.0814952282046 2004 1877.724433749061 2005 2126.570639392355 2006 2411.81131513 2007 2816.2953148339493 2008 3308.8972592091845 2009 3614.465987220654 2010 3937.2851672575525 2011 4107.6396197749045 2012 4600.414515577314 2013 4688.8215032871885 2014 4535.164900641207 2015 4094.3906595892718 2016 3993.2257195435463 2017 3827.633419361467 2018 3733.69737125349 2019 3597.7964597299297 2020 3205.420956780546 2021 3513.9770118089664 2022 3874.889380986961 2023 3968.0509907644037