Year Percent 1960 -1.02512 1961 -2.55265 1962 -0.2247 1963 -0.28048 1964 -0.81307 1965 -0.45972 1966 -9.3384 1967 -8.09153 1968 -4.7074 1969 -5.8131 1970 -2.99401 1971 -2.22222 1972 -2.37949 1973 0.57304 1974 7.57751 1975 0.57425 1976 1.34159 1977 3.41176 1978 1.01952 1979 6.47611 1980 8.29429 1981 2.08359 1982 -3.91816 1983 -1.06842 1984 4.51934 1985 2.83697 1986 -0.01833 1987 2.17935 1988 2.82876 1989 3.09323 1990 1.71966 1991 1.86296 1992 3.18749 1993 2.98624 1994 1.14575 1995 -1.33426 1996 -0.61564 1997 -0.27537 1998 9.75008 1999 8.08435 2000 10.51774 2001 8.27107 2002 6.29578 2003 7.33882 2004 4.67209 2005 4.1466 2006 5.41231 2007 4.04219 2008 1.05517 2009 2.80612 2010 1.89679 2011 2.47469 2012 -0.39414 2013 -0.79022 2014 -0.74821 2015 0.38272 2016 0.80301 2017 1.20539