Year Percent 1961 2.9889 1962 -0.82051 1963 -4.80583 1964 0.79151 1965 -1.60985 1966 0.04027 1967 -1.33825 1968 7.94495 1969 3.97639 1970 4.71233 1971 4.22209 1972 4.26353 1973 5.33462 1974 4.91315 1975 2.36027 1976 4.2652 1977 6.13862 1978 4.22913 1979 4.8004 1980 7.31963 1981 5.43342 1982 -0.08787 1983 1.86044 1984 4.65053 1985 0.31581 1986 3.74385 1987 2.8932 1988 3.80272 1989 5.50783 1990 5.34858 1991 5.07092 1992 4.71082 1993 4.75934 1994 5.84006 1995 6.56472 1996 6.22343 1997 3.19688 1998 -14.34678 1999 -0.60856 2000 3.4679 2001 2.21034 2002 3.05741 2003 3.33743 2004 3.58917 2005 4.24826 2006 4.06629 2007 4.90681 2008 4.59061 2009 3.23819 2010 4.82944 2011 4.79425 2012 4.67712 2013 4.23837 2014 3.73124 2015 3.645 2016 3.8453 2017 3.92307