Year Percent 1970 -2.93108 1971 0.78684 1972 2.9703 1973 0.14956 1974 -12.19249 1975 -6.85729 1976 -2.57658 1977 -1.60209 1978 0.74116 1979 -1.56235 1980 -1.08804 1981 -3.05567 1982 -2.9498 1983 -1.16769 1984 -2.54947 1985 -2.11156 1986 0.50386 1987 2.2404 1988 3.95452 1989 0.71816 1990 0.91509 1991 3.68621 1992 3.15034 1993 3.65617 1994 2.7497 1995 1.8725 1996 1.58159 1997 1.3939 1998 1.33861 1999 0.49987 2000 2.97401 2001 3.62826 2002 3.03815 2003 1.76468 2004 0.28727 2005 -1.44843 2006 -0.3858 2007 0.12096 2008 -0.25103 2009 2.32277 2010 2.2946 2011 1.54801 2012 0.69572 2013 1.57966 2014 0.72821 2015 0.75931 2016 0.3126