Year current US$ 1971 175.5797885295445 1972 191.35938368669434 1973 238.58130195487334 1974 290.48049330442706 1975 312.09355962249055 1976 327.01288409020657 1977 335.8537711872869 1978 369.2388598813546 1979 403.06225475988475 1980 526.222742107111 1981 813.2089162890225 1982 723.409680572307 1983 606.5102310236346 1984 512.1230955886205 1985 451.6415804375705 1986 449.51824223212674 1987 489.7559476738229 1988 502.08282799358955 1989 473.3689894760608 1990 519.810335256057 1991 531.8502934956919 1992 514.5297510920353 1993 466.6238672661059 1994 442.1432526976629 1995 503.45958121414964 1996 510.08256378476943 1997 518.8893565116235 1998 495.33514775796937 1999 493.6167638519553 2000 487.0381825381712 2001 455.915451566865 2002 486.6442707149085 2003 599.7515977285601 2004 723.5277340949228 2005 820.6943861334343 2006 958.6042291598875 2007 1047.913079405342 2008 1115.9043615538344 2009 1116.4357311407914 2010 1253.0174745883057 2011 1353.9769400441676 2012 1399.955789205424 2013 1470.1025341348734 2014 1544.103479338012 2015 1379.5406479514793 2016 1260.5706333214403 2017 1313.1901517712852 2018 1319.4315994580393 2019 1313.8986830575755 2020 1228.8056819274882 2021 1306.186268828245