Year current US$ 1970 196.89899722144816 1971 139.40131919206559 1972 163.3321126807213 1973 195.09963297452046 1974 242.79509684202813 1975 292.3428943369876 1976 351.0220428320964 1977 349.5438947755269 1978 382.7546942966575 1979 393.13951678002434 1980 516.6473009791868 1981 1110.7102914277098 1982 976.5617813486496 1983 688.1306161176072 1984 544.7630594593304 1985 532.627900810825 1986 492.8683246914962 1987 478.27021865264743 1988 471.6983841796087 1989 393.47384289172936 1990 445.7217724632869 1991 439.96907214219857 1992 425.8210872739057 1993 336.7838193396277 1994 288.7101902737737 1995 354.66465996944214 1996 383.1729128810952 1997 380.81836165922266 1998 394.8787563913647 1999 413.6977052966249 2000 365.47533212707987 2001 397.20410036534383 2002 476.40222017816353 2003 528.934057874505 2004 627.7589558231027 2005 729.7473538977309 2006 972.9953664545569 2007 1096.522058726543 2008 1284.3821208675834 2009 1164.60126974899 2010 1278.343050126844 2011 1375.4590526350346 2012 1484.1968673250199 2013 1679.9656665406353 2014 1838.4648128158913 2015 1589.531108363909 2016 1397.764260111893 2017 1316.043520180272 2018 1412.503047004975 2019 1440.3278604843929 2020 1399.1519799327557 2021 1415.9825086756148