Year Percent 1961 -0.00003 1962 0.00001 1963 0.00002 1964 -0.00001 1965 5.19692 1966 2.73347 1967 -5.85071 1968 6.66698 1969 14.16496 1970 -2.14247 1971 -6.92937 1972 5.95028 1973 23.22516 1974 14.16091 1975 8.86874 1976 8.28421 1977 19.74695 1978 23.85011 1979 11.53571 1980 -6.00873 1981 8.69831 1982 18.50163 1983 19.43896 1984 39.76726 1985 68.88971 1986 78.5038 1987 165.67664 1988 64.28825 1989 61.49128 1990 70.59155 1991 128.76167 1992 82.02358 1993 26.73632 1994 25.06204 1995 33.59799 1996 29.58049 1997 2.25277 1998 23.77512 1999 17.19385 2000 3.28114 2001 73.83711 2002 -3.91622 2003 13.14347 2004 12.81586 2005 16.62996 2006 12.32894 2007 6.79633 2008 9.99371 2009 7.78176 2010 17.17712 2011 17.37418 2012 12.04108 2013 6.92515 2014 1.79731 2015 18.86476 2016 1.77562 2017 14.67784