Year Percent 1961 0.23253 1962 -0.86276 1963 0.01772 1964 2.79409 1965 2.39945 1966 5.19718 1967 4.217 1968 2.23619 1969 4.63501 1970 3.96056 1971 2.18741 1972 1.38568 1973 -4.89932 1974 1.85246 1975 -6.20477 1976 2.3329 1977 -1.25738 1978 1.81202 1979 0.12061 1980 -7.21836 1981 -5.59351 1982 -6.00525 1983 -5.21193 1984 -4.65442 1985 -2.35679 1986 -2.0929 1987 -0.51317 1988 -0.86858 1989 -25.5137 1990 -50.23014 1991 -12.68625 1992 -33.88099 1993 -32.22209 1994 -22.25353 1995 -7.06401 1996 6.09873 1997 91.64805 1998 20.37804 1999 13.57394 2000 21.92751 2001 -0.74951 2002 1.33268 2003 -31.34159 2004 0.67633 2005 2.54387 2006 4.37515 2007 5.26024 2008 2.75748 2009 1.19656 2010 2.4291 2011 4.95567 2012 5.1175 2013 6.04789 2014 -1.69432 2015 -2.41985 2016 -4.03561 2017 -0.10212