Year Percent 1961 2.65602 1962 4.72213 1963 -2.59342 1964 0.85719 1965 2.24102 1966 -1.02109 1967 7.05836 1968 1.3443 1969 0.28879 1970 -1.59935 1971 -0.33697 1972 0.52366 1973 -1.33439 1974 6.32226 1975 1.08212 1976 6.4678 1977 -1.58873 1978 2.49536 1979 1.47629 1980 -1.43667 1981 1.83268 1982 6.91285 1983 -2.15074 1984 -4.26104 1985 5.75574 1986 5.19496 1987 -2.80246 1988 3.05797 1989 -0.51091 1990 -3.21121 1991 6.189 1992 -2.43052 1993 0.69559 1994 -1.41084 1995 2.85299 1996 7.98735 1997 3.39812 1998 4.34171 1999 4.41532 2000 -1.03264 2001 3.60862 2002 1.39457 2003 4.72271 2004 1.46414 2005 5.49346 2006 3.12417 2007 2.52032 2008 4.09748 2009 -0.1074 2010 2.23944 2011 3.46632 2012 3.30938 2013 2.68496 2014 1.28202 2015 0.88482 2016 2.88081 2017 3.70083