Year current US$ 1960 477.786990828994 1961 624.7186325846211 1962 680.2995183444343 1963 592.2116793293216 1964 742.9520683696873 1965 706.2693549482459 1966 666.9876416425217 1967 584.6384724850466 1968 578.2248707414685 1969 722.5906832265127 1970 765.9117589883213 1971 1000.629502602798 1972 775.8361726554069 1973 1397.6872615315651 1974 1433.787561471232 1975 1231.921867384783 1976 1268.6258334848576 1977 1414.201588719531 1978 1678.3304335812873 1979 2442.0773299389293 1980 3440.528157864137 1981 3725.0032159483894 1982 3081.0473943602265 1983 1704.5659103170576 1984 1612.31925995459 1985 1564.707925613724 1986 1933.481231422897 1987 2408.6325986085785 1988 2668.674090522443 1989 2724.0974341128563 1990 2983.244161491772 1991 3574.1116214229974 1992 4083.463271684076 1993 4729.928639066889 1994 5478.022002226315 1995 6014.918522753682 1996 6358.162863141135 1997 7386.511422067339 1998 7780.6783489302625 1999 7314.490950529247 2000 6932.47813396337 2001 6331.156601875593 2002 4115.154549131948 2003 3638.9435907085854 2004 4130.1001146777 2005 5233.457170586684 2006 5942.126748990643 2007 7149.374633867964 2008 9328.065708199323 2009 9780.739617864094 2010 12512.594126844118 2011 14975.56281867366 2012 16087.25207779731 2013 18140.892213305906 2014 18131.578846566077 2015 16950.753169481555 2016 16837.94038030493 2017 18995.397019555403 2018 19067.291555573716 2019 18149.056290831475 2020 15651.003377537532 2021 17733.855164390214 2022 20499.24222444518 2023 22564.53246206867