Year Percent 1961 3.18841 1962 -5.41071 1963 -2.52924 1964 0.13832 1965 -1.03099 1966 -1.39169 1967 2.5011 1968 -0.71837 1969 4.88807 1970 0.29099 1971 -0.81631 1972 -1.88048 1973 -0.03243 1974 4.25695 1975 -1.67795 1976 3.13038 1977 1.44272 1978 -1.21501 1979 -4.94139 1980 -7.04476 1981 -4.35432 1982 4.50739 1983 -10.86418 1984 6.38101 1985 1.22752 1986 1.16806 1987 -6.94913 1988 -0.35135 1989 -0.16773 1990 -4.38139 1991 -3.02152 1992 -8.87797 1993 -2.3587 1994 2.12476 1995 4.47919 1996 -6.3207 1997 2.86038 1998 2.36957 1999 1.37038 2000 -4.52737 2001 2.35983 2002 1.61695 2003 -7.15695 2004 4.07703 2005 -0.87322 2006 2.92968 2007 2.7961 2008 0.41986 2009 0.35032 2010 2.02058 2011 2.66312 2012 3.7821 2013 -36.8299 2014 0.68783 2015 4.09198 2016 3.42739 2017 2.85693