Year constant 2015 US$ 1965 21974.01521074821 1966 23229.23586006258 1967 21352.999334019663 1968 23683.823259437573 1969 22243.472133077492 1970 21821.445273615194 1971 23596.490066453247 1972 21715.20719843938 1973 22617.921369989446 1974 25808.73671805254 1975 23756.381953503173 1976 24899.860305775856 1977 24624.16173497955 1978 26226.202672187614 1979 26427.644435200033 1980 25739.595166497227 1981 25591.407216096068 1982 25212.369367892505 1983 25144.706193777118 1984 25161.444271765133 1985 24279.31527571894 1986 26906.220315022692 1987 26602.86832900908 1988 25024.66664352486 1989 24966.797636924155 1990 24464.159536656767 1991 24845.85590790104 1992 24018.095626986884 1993 23272.69193372569 1994 22486.059503842796 1995 22034.32785841214 1996 21538.69145692199 1997 21166.024901385917 1998 21191.940940432993 1999 21247.9869529184 2000 21578.599854580814 2001 21157.334901846003 2002 20999.77383246608 2003 21117.523442338275 2004 21006.61966814162 2005 20766.378705095703 2006 20658.377816376797 2007 20763.088509008983 2008 20588.346501545937 2009 19596.68344024134 2010 19012.05333387817 2011 18353.40248002032 2012 18099.479902374864 2013 18080.30796176072 2014 18072.113791890457 2015 18252.514203209405 2016 18573.384925396822 2017 19260.619532475466 2018 19471.39010618082 2019 19856.259059083797 2020 18321.527964577148 2021 18575.386202645004 2022 19262.613199834108