Year current US$ 1960 5.245855737052421 1961 5.208097049196788 1962 1.5984912187325069 1963 4.270884940176705 1964 4.146658795648615 1965 4.334734833142118 1966 4.221398187924466 1967 5.416024631428328 1968 4.578852029597022 1969 5.957228429343024 1970 5.49654235559981 1971 6.54685840510996 1972 5.87743512803616 1973 5.671348123434204 1974 8.232373180687192 1975 6.078100273182979 1976 7.970893769756819 1977 11.16241245274657 1978 10.214166073114345 1979 8.141587635020128 1980 9.880113519416566 1981 13.928497234466612 1982 22.200845975956508 1983 13.244493957213495 1984 11.870646714117546 1985 9.475327096776748 1986 14.543346644047253 1987 15.86766741045311 1988 16.79569718396327 1989 23.50372909962068 1990 14.367380649321897 1991 32.05857086167741 1992 16.852733771716704 1993 24.23052991615457 1994 20.094316672243906 1995 26.349301596573962 1996 15.277010595413627 1997 17.022639497769106 1998 12.32672434033723 1999 14.731306057508856 2000 15.650436215917523 2001 13.218738831690741 2002 12.482710313297218 2003 12.235548696176195 2004 6.378864934420558 2005 11.616106645407257 2006 12.465049504039442 2007 21.852743294155875 2008 24.808916090731017 2009 28.61164163097384 2010 19.47781912399948 2011 13.685975051576273 2012 17.653944812526486 2013 21.76449896095661 2014 10.248375876837127 2015 9.741095396559668 2016 14.128840038127011 2017 22.461199948893885 2018 25.5520127781246 2019 19.517532847226338 2020 46.04079973262524 2021 26.125484876507787 2022 14.263921661207545