Year Percent 1960 -1.61527 1961 -1.66205 1962 -2.36613 1963 -2.7897 1964 -0.99404 1965 -0.83721 1966 -1.57356 1967 -0.85106 1968 -1.39683 1969 -1.14155 1970 -1.93384 1971 -2.92784 1972 -2.52508 1973 -2.06044 1974 -5.54659 1975 -6.81043 1976 -5.80661 1977 -6.89198 1978 -3.14179 1979 -2.66369 1980 -6.76595 1981 -4.66776 1982 -3.15282 1983 -4.08463 1984 -4.0669 1985 -3.10553 1986 -2.78958 1987 -2.1766 1988 1.10111 1989 -1.57784 1990 -4.21279 1991 -2.79375 1992 -2.95289 1993 -5.66948 1994 0.97841 1995 -4.45942 1996 -6.284 1997 -5.80689 1998 0.86233 1999 -0.2459 2000 -3.10305 2001 3.75701 2002 1.46085 2003 -1.11521 2004 -2.61872 2005 -3.40158 2006 -4.85027 2007 -4.84914 2008 -4.25381 2009 -0.78513 2010 -5.0016 2011 -8.13813 2012 -4.91058 2013 -5.80581 2014 -3.88543 2015 -2.60801 2016 -2.88548 2017 -4.49336