Year current US$ 1970 2436.4721160940044 1971 2662.6380595813066 1972 3061.612888136812 1973 3663.403333555908 1974 3986.094411508386 1975 4410.536772423863 1976 4754.42730466367 1977 5328.506906168056 1978 6372.341436401761 1979 7167.38496361703 1980 7808.890875275203 1981 7849.818575831706 1982 7801.042952244851 1983 8013.0662111294805 1984 8395.722187353556 1985 8783.741023874649 1986 10689.756276372213 1987 12336.890113303036 1988 13898.585138729517 1989 14326.046730900218 1990 15893.326414885483 1991 16622.29381089271 1992 17694.385754092586 1993 17590.23491159222 1994 18853.819598542173 1995 20789.468010822136 1996 20853.23404533044 1997 20423.694337571666 1998 20528.56784158101 1999 21393.527657399332 2000 21649.45177121135 2001 21358.764559375002 2002 22121.274369463335 2003 24639.76127950329 2004 27327.167208185336 2005 28585.475691149975 2006 30048.56437080777 2007 32326.18734710654 2008 33445.74435967606 2009 31273.50097259616 2010 32845.735125123145 2011 35243.65239001519 2012 35222.16297809727 2013 35395.14114437627 2014 36065.27174537608 2015 34030.46913769711 2016 34510.02670894941 2017 35939.42965788556 2018 37872.03202353181 2019 38071.2773858291 2020 36747.245342897244 2021 40485.32897586899