Year Percent 1961 -4.24012 1962 3.04751 1963 3.70103 1964 -2.47877 1965 2.75322 1966 -5.57303 1967 4.60953 1968 8.92237 1969 -0.05427 1970 1.87372 1971 6.63537 1972 11.10992 1973 21.1827 1974 57.51167 1975 24.57146 1976 7.99564 1977 13.34229 1978 3.16483 1979 24.70798 1980 36.94976 1981 7.59171 1982 12.15122 1983 6.34017 1984 6.01071 1985 1.2396 1986 -1.24695 1987 4.85228 1988 4.15569 1989 7.18089 1990 15.48974 1991 1.9981 1992 4.19654 1993 9.67785 1994 13.2692 1995 3.326 1996 1.84954 1997 -3.54357 1998 -1.85648 1999 4.30318 2000 12.04315 2001 2.79395 2002 -5.19253 2003 10.47815 2004 8.88469 2005 13.32137 2006 1.72921 2007 12.75187 2008 23.7941 2009 -27.63265 2010 12.73322 2011 15.7297 2012 -0.22529 2013 2.92965 2014 2.06296 2015 -12.06235 2016 1.63381 2017 3.03875