Year constant 2015 US$ 1960 19087.682252448103 1961 20119.39557307048 1962 21150.96241147519 1963 22260.56836760705 1964 23508.958832601566 1965 24873.114999058238 1966 25968.91047723225 1967 27224.725444363816 1968 28222.51408493358 1969 29459.5536493074 1970 26804.595919398827 1971 26456.892465228953 1972 24891.09246372937 1973 26168.599673793942 1974 21321.177315457935 1975 17794.804408209937 1976 18334.694511262627 1977 19591.349471420875 1978 21903.021459260923 1979 27073.046095445825 1980 28274.090946437398 1981 25192.08332320105 1982 26391.00016905013 1983 26830.78626700092 1984 30051.2631473717 1985 30891.61840219544 1986 30836.247476955155 1987 31158.496612960553 1988 31286.506688867747 1989 32757.242836412286 1990 31616.77035789745 1991 29704.333139555114 1992 27968.693828029744 1993 27452.04610902709 1994 27754.67926687413 1995 28432.5681444605 1996 29110.694413905472 1997 28987.631992687042 1998 29851.856870498 1999 31497.75429631003 2000 32325.792211500986 2001 32710.503480163014 2002 33155.15203382206 2003 32301.727215306702 2004 32149.93406474907 2005 32791.13127407819 2006 33153.0893732904 2007 33162.16157660349 2008 31933.65482822605 2009 30162.80494953636 2010 30199.018786997993 2011 30008.1161367305 2012 30575.161320968054 2013 29423.30362280475 2014 29698.75831703627 2015 29722.406842934884 2016 29192.74645300182 2017 29781.065814051963 2018 30344.79960012499 2019 29736.79422414192 2020 23256.11606416502 2021 26743.874030304774 2022 29477.235853272065 2023 30061.654651319983