Year Percent 1961 -15.72629 1962 -21.6451 1963 31.00795 1964 3.16386 1965 3.42297 1966 -7.39612 1967 6.38818 1968 7.65084 1969 5.36643 1970 5.82801 1971 -13.76223 1972 23.96859 1973 1.00618 1974 4.566 1975 2.14097 1976 5.3531 1977 2.28386 1978 6.08368 1979 4.33592 1980 -2.21655 1981 -0.12946 1982 3.13165 1983 2.15986 1984 2.3898 1985 0.61163 1986 -2.51752 1987 -3.50914 1988 -3.71175 1989 1.64642 1990 -1.74679 1991 -3.58853 1992 -0.54739 1993 -4.23219 1994 -2.91257 1995 1.85342 1996 2.30509 1997 -0.50825 1998 3.54479 1999 1.75801 2000 2.42788 2001 1.67648 2002 4.27945 2003 5.85052 2004 2.94323 2005 4.45275 2006 0.21097 2007 1.7992 2008 0.71395 2009 -0.1016 2010 1.76368 2011 0.93036 2012 1.32111 2013 0.69635 2014 1.73328 2015 1.79025 2016 1.4314 2017 -0.05273