Year current US$ 1971 160.65162755042078 1972 171.89427367087444 1973 188.25466184687133 1974 229.73334977014633 1975 233.3616618224988 1976 206.63024235812574 1977 234.24278545890147 1978 157.54866604348263 1979 216.1644499522751 1980 253.89951158853813 1981 271.91534935425204 1982 293.40629534090544 1983 310.31854263894263 1984 351.9671585486919 1985 352.3137695798398 1986 372.8424785789327 1987 382.9331394116113 1988 396.355013819619 1989 391.2533999095775 1990 443.87235329831844 1991 487.7152527534278 1992 523.2337932562166 1993 551.8107218460865 1994 613.9945516762785 1995 671.0789448672848 1996 708.9965087878209 1997 768.0250641616569 1998 784.8168333803806 1999 771.1939783302306 2000 799.5532156940071 2001 772.9611703103417 2002 806.9406808343512 2003 918.265721153152 2004 989.1800241135816 2005 1152.9671414814861 2006 1315.921645758505 2007 1494.4687382999757 2008 1834.1940997407426 2009 1908.7049691232023 2010 2632.4071840290785 2011 3005.0279778340846 2012 3073.687180481114 2013 3306.896376708315 2014 3513.4826904906845 2015 3614.457178200337 2016 3718.4799191522866 2017 3957.8897913281803 2018 3936.0460007531287 2019 3671.8493963810024 2020 3490.725902109042 2021 3611.5912358045584