Year Percent 1961 2.88785 1962 0.12468 1963 2.36993 1964 6.66458 1965 -1.85784 1966 0.38068 1967 -0.11234 1968 3.91864 1969 9.43521 1970 3.99216 1971 1.6928 1972 5.31293 1973 7.12277 1974 2.8623 1975 -7.58648 1976 2.0281 1977 1.39354 1978 3.88839 1979 2.10614 1980 0.48255 1981 -0.84367 1982 1.04829 1983 2.96175 1984 6.07785 1985 2.59325 1986 9.49157 1987 3.27947 1988 7.67911 1989 8.73531 1990 4.00981 1991 7.19841 1992 0.47608 1993 2.81122 1994 2.41663 1995 0.0173 1996 0.01774 1997 4.39291 1998 4.73376 1999 7.02569 2000 6.7947 2001 1.31861 2002 2.73747 2003 0.40176 2004 2.14992 2005 1.60586 2006 3.51414 2007 6.694 2008 -3.02853 2009 -6.11337 2010 2.96812 2011 0.28528 2012 -2.71709 2013 1.28621 2014 3.30804 2015 0.46261 2016 0.88466 2017 -0.6774