Year Percent 1961 0.61812 1962 4.48067 1963 2.90827 1964 4.34055 1965 5.0781 1966 5.27711 1967 1.38995 1968 3.75882 1969 2.09737 1970 2.01142 1971 1.9977 1972 4.14241 1973 4.63958 1974 -1.42195 1975 -1.17688 1976 4.38943 1977 3.56175 1978 4.44909 1979 2.04333 1980 -1.19726 1981 1.59252 1982 -2.84155 1983 3.68008 1984 6.33443 1985 3.31913 1986 2.5594 1987 2.5411 1988 3.26208 1989 2.70597 1990 0.77452 1991 -1.40047 1992 2.12911 1993 1.39986 1994 2.76962 1995 1.50307 1996 2.59531 1997 3.23659 1998 3.23939 1999 3.48993 2000 2.94029 2001 -0.01849 2002 0.84613 2003 1.92696 2004 2.82965 2005 2.39705 2006 1.68142 2007 0.81519 2008 -1.23028 2009 -3.62412 2010 1.68111 2011 0.8497 2012 1.45929 2013 0.95672 2014 1.80046 2015 2.08708 2016 0.74279 2017 1.547