Year current US$ 1970 496.73542829852374 1971 546.7218518108559 1972 602.1085345151728 1973 775.8079617436779 1974 990.9433590999588 1975 1030.69168511659 1976 1104.3880058046423 1977 1168.1683764526895 1978 1288.8971392347796 1979 1462.1907818895386 1980 1677.6094176457773 1981 1892.0780021353078 1982 1688.4344781841073 1983 1407.0514055159163 1984 1403.5040062754322 1985 1349.372345757169 1986 1356.5486697713573 1987 1419.5861432157292 1988 1571.6639468629737 1989 1741.5944720430298 1990 1988.9797842444013 1991 2147.7580274239745 1992 2306.6970417918174 1993 2689.2924289997536 1994 3128.657806045903 1995 3288.1280655198307 1996 3553.974876398838 1997 3810.180855932437 1998 3746.397330189373 1999 3217.519267602508 2000 3481.397036617384 2001 3348.529523665319 2002 2945.431288676007 2003 2943.460743274973 2004 3287.4409499265457 2005 3893.3350865380994 2006 4532.001097276478 2007 5328.219056493355 2008 6036.197544342771 2009 5552.369443017363 2010 6784.225803276941 2011 7707.4461484723215 2012 7509.559333359218 2013 7698.978206770986 2014 7672.373714114054 2015 6556.88975282871 2016 6275.950218436621 2017 6961.161630545739 2018 6604.482552432204 2019 6471.220360504532 2020 5394.17674922795 2021 5983.854770192632