Year current US$ 1960 2.6951377398768246 1961 2.8539458632120454 1962 2.8798307744728215 1963 3.2664808160366303 1964 3.64790429765873 1965 3.727928442843703 1966 3.62942994506845 1967 3.6873182921030576 1968 3.0498531326549148 1969 2.9752332024978148 1970 3.1169825587318596 1971 3.3274791277663134 1972 3.2688884754317282 1973 4.449328354276318 1974 6.310484830980729 1975 8.400469278395379 1976 7.8596133071589005 1977 7.709806104362208 1978 9.051513206691453 1979 9.455718869359437 1980 11.555046413253699 1981 10.21065283955462 1982 9.385880848170943 1983 8.433966264962182 1984 8.298129041632636 1985 8.32887590888298 1986 9.73558456192168 1987 9.905741149020246 1988 10.704287688277885 1989 10.853242892492048 1990 15.081833672648742 1991 15.545455087456801 1992 14.438917418241276 1993 11.43437599271025 1994 13.19784689248217 1995 12.16404880329024 1996 11.14178783352685 1997 9.398504081930243 1998 9.671391609074677 1999 9.07684214099941 2000 8.505942995564704 2001 9.327662655223845 2002 9.436091944449997 2003 10.077151077086043 2004 11.31565316010834 2005 14.050735976987928 2006 16.71942999924429 2007 11.955135388515263 2008 12.611979855032203 2009 13.311479187932655 2010 16.226599543657123 2011 16.20061797154572 2012 17.321639505096 2013 20.420477219761697 2014 19.226131857687346 2015 17.585061845540107 2016 16.647666479123412 2017 17.341600341918777 2018 16.14262263019051 2019 16.81422300105332 2020 20.860381806647393 2021 21.311515625260853 2022 28.530152931896367