Year current US$ 1971 235.31703528608244 1972 199.39563455388625 1973 224.09836638852252 1974 256.9622793225381 1975 236.50659669647973 1976 226.28055767034868 1977 252.092247217455 1978 286.9176781374181 1979 304.64986555501264 1980 319.3229611292088 1981 301.0778991082907 1982 276.9762607945871 1983 270.1494295745206 1984 282.485505020893 1985 280.19508216748955 1986 345.8080489549805 1987 296.00443465632367 1988 295.85813831397394 1989 292.69779379217346 1990 315.87395189089233 1991 348.48417181593544 1992 326.6379734944311 1993 287.9233718091585 1994 244.58205057713306 1995 283.3519813675843 1996 295.31420496920646 1997 290.2727571441731 1998 308.7486560423866 1999 327.08618947799454 2000 190.3497116495831 2001 202.33114927389448 2002 226.12055400089054 2003 262.88326937284035 2004 310.8287284939984 2005 376.2137152011457 2006 739.3080478973734 2007 866.1538767405705 2008 977.8787765160793 2009 855.4245711060368 2010 1023.8612528058276 2011 1143.8766987060988 2012 1151.2858763114994 2013 1839.7889570629002 2014 1489.1438905729774 2015 1350.6952929389274 2016 1517.5100532221925 2017 1556.1538831975747 2018 1728.1659101030652 2019 1728.3921910505044 2020 1835.4034403041592 2021 1823.9029219527465