Year Percent 1961 -2.58426 1962 4.08276 1963 -5.46212 1964 -3.82261 1965 3.81674 1966 -6.28718 1967 -1.46828 1968 -0.98061 1969 -1.56932 1970 2.8032 1971 -0.79022 1972 -7.91573 1973 -2.42355 1974 7.99803 1975 12.05969 1976 12.92034 1977 2.77432 1978 -9.01839 1979 -8.16634 1980 -1.8627 1981 3.82498 1982 2.39104 1983 -1.31604 1984 -8.03172 1985 -9.10556 1986 2.42124 1987 11.14265 1988 -2.91881 1989 6.14675 1990 -7.88824 1991 4.75056 1992 3.8363 1993 1.86166 1994 -1.63573 1995 3.19005 1996 3.0781 1997 7.56694 1998 1.45249 1999 0.26378 2000 3.40686 2001 3.54729 2002 3.47184 2003 4.75742 2004 1.04806 2005 4.60615 2006 7.16839 2007 8.63728 2008 5.04604 2009 0.61404 2010 0.83479 2011 7.88947 2012 12.81521 2013 1.95913 2014 0.26331 2015 2.43623 2016 2.23711 2017 1.82735