Year Percent 1961 2.92715 1962 -1.82872 1963 2.81653 1964 -4.28169 1965 1.57193 1966 -1.67012 1967 4.98673 1968 -1.21187 1969 8.88039 1970 18.6316 1971 5.34391 1972 4.71585 1973 -0.82025 1974 3.13339 1975 -5.04914 1976 -2.60773 1977 -9.63391 1978 -5.62852 1979 0.03465 1980 10.54954 1981 8.47121 1982 -1.215 1983 -2.28736 1984 -5.60697 1985 3.03334 1986 -1.51062 1987 -2.30043 1988 4.06947 1989 2.03143 1990 4.04072 1991 2.90507 1992 -11.05812 1993 -1.0138 1994 7.16002 1995 -1.64156 1996 8.46439 1997 0.99934 1998 1.29975 1999 -2.22579 2000 -4.3101 2001 0.25909 2002 -9.87326 2003 -17.87133 2004 -6.86622 2005 -6.89531 2006 -4.81668 2007 -5.13968 2008 -19.05683 2009 9.9745 2010 10.37743 2011 13.03572 2012 12.25024 2013 3.12064 2014 -0.23973 2015 -0.66792 2016 -1.7075 2017 1.07185