Year Percent 1960 -8.59167 1961 -6.48172 1962 -3.98872 1963 -7.43177 1964 -4.47006 1965 -3.79527 1966 -4.53505 1967 -2.01967 1968 0.60665 1969 -2.47163 1970 -5.798 1971 -6.4001 1972 -8.12272 1973 -6.62557 1974 -14.96235 1975 -11.84217 1976 -11.37165 1977 -6.40284 1978 -7.76752 1979 -13.96439 1980 -7.43932 1981 -9.14453 1982 -3.16561 1983 1.13996 1984 -2.86277 1985 -3.17516 1986 -3.10937 1987 -3.86337 1988 1.95298 1989 -5.08032 1990 -6.80696 1991 -11.54205 1992 -12.1658 1993 -11.5619 1994 -11.52492 1995 -13.21118 1996 -13.43277 1997 -11.36717 1998 -15.96275 1999 -12.97878 2000 -9.96778 2001 -5.82749 2002 -6.57224 2003 -6.0133 2004 -8.11726 2005 -6.69273 2006 -5.54879 2007 -6.65337 2008 -10.51981 2009 0.64746 2010 -8.18978 2011 -6.02679 2012 -7.67615 2013 -7.31065 2014 -8.37565 2015 -4.63214 2016 -4.52358