Year Percent 1961 1.17629 1962 -2.79158 1963 -1.01716 1964 1.27748 1965 -0.04741 1966 1.99017 1967 -4.61028 1968 0.98263 1969 5.09692 1970 1.79576 1971 -0.55139 1972 -1.43041 1973 0.25239 1974 2.82291 1975 5.86813 1976 3.5237 1977 0.89881 1978 4.68293 1979 5.46361 1980 5.12629 1981 0.89319 1982 -10.34576 1983 -10.85319 1984 -1.77627 1985 0.8176 1986 8.12307 1987 7.32293 1988 0.8483 1989 0.45306 1990 -0.38006 1991 2.80952 1992 7.1514 1993 1.90493 1994 6.4955 1995 -2.15652 1996 4.82283 1997 7.78526 1998 3.84812 1999 -2.44829 2000 -2.28211 2001 -4.01343 2002 -7.75058 2003 0.87003 2004 5.05284 2005 7.41115 2006 3.92885 2007 6.26403 2008 6.82165 2009 3.87364 2010 7.4309 2011 4.81397 2012 3.19822 2013 4.2928 2014 2.89036 2015 0.01957 2016 1.32207 2017 2.27822