Year Percent 1961 0.32559 1962 0.31609 1963 0.27226 1964 5.76904 1965 -2.88268 1966 5.1507 1967 -3.37138 1968 -1.2224 1969 2.44539 1970 0.55442 1971 -3.17925 1972 1.00865 1973 -2.54676 1974 4.08755 1975 -0.71651 1976 2.13525 1977 0.75968 1978 2.09538 1979 0.08288 1980 -4.51834 1981 5.87768 1982 1.39737 1983 -5.20754 1984 7.1797 1985 3.75395 1986 2.25937 1987 -0.51379 1988 5.33034 1989 1.93522 1990 2.09083 1991 3.62868 1992 1.32277 1993 1.05239 1994 5.3847 1995 0.90909 1996 2.89026 1997 2.76641 1998 0.9138 1999 2.39793 2000 4.25449 2001 2.97429 2002 -1.52854 2003 2.34411 2004 3.19846 2005 2.14398 2006 2.1679 2007 2.32979 2008 5.05861 2009 3.49622 2010 3.72247 2011 2.27128 2012 3.558 2013 2.88096 2014 4.72441 2015 2.12209 2016 -0.71825 2017 6.31738