Year current US$ 1960 -0.4576837471741292 1961 3.2436447169419096 1962 2.9350652441476215 1963 4.131089433621299 1964 2.3754556793543133 1965 2.1777415351819895 1966 4.435074968351692 1967 4.92711898863908 1968 5.913698774787755 1969 5.214722423066463 1970 6.373038841218528 1971 4.863255778999498 1972 4.691740789936366 1973 5.769698448678171 1974 3.800789985204166 1975 3.0136220066491495 1976 2.838205037852713 1977 1.6466258325278844 1978 2.302467695655131 1979 1.544606881172469 1980 1.6144438991814205 1981 1.9909668359761723 1982 2.2535873426596873 1983 1.5608546800004985 1984 1.7407348782875978 1985 1.7908864088964533 1986 1.6762293698777282 1987 2.673589888655019 1988 2.5559297808004144 1989 2.354406797497544 1990 3.099560900718506 1991 3.948290321918305 1992 7.033493397201582 1993 3.069502048766226 1994 2.6054341402276258 1995 5.052807608185476 1996 5.32476923088624 1997 5.11584991513441 1998 4.7255966993875305 1999 8.251386097889641 2000 5.160507419321341 2001 10.038688394592683 2002 11.327914257426018 2003 19.874475637168747 2004 12.870403861617367 2005 15.23106798011174 2006 23.49010133363337 2007 17.14473750130523 2008 22.36660959149145 2009 23.918220413232483 2010 15.018930846370438 2011 22.370661155449174 2012 16.69243392508362 2013 18.544947415871558 2014 26.225875871218374 2015 28.776058383556673 2016 23.23291974374855 2017 17.587189388287904 2018 36.141635259769366 2019 17.408550711734453 2020 36.70401899255816 2021 37.20997635111869 2022 36.30545528131286