Year Percent 1961 2.93058 1962 1.74451 1963 3.5266 1964 0.32597 1965 -1.23154 1966 8.8481 1967 1.41422 1968 1.43313 1969 1.83865 1970 -0.1474 1971 7.38671 1972 -2.78925 1973 -6.6635 1974 0.67934 1975 -14.3181 1976 2.20385 1977 8.75635 1978 6.08162 1979 6.79563 1980 6.36333 1981 4.9151 1982 -12.36789 1983 -6.48028 1984 2.4697 1985 2.34171 1986 3.64966 1987 4.68499 1988 5.54432 1989 8.09407 1990 1.64542 1991 6.08116 1992 9.42827 1993 4.96389 1994 3.4745 1995 7.36959 1996 5.32062 1997 5.98764 1998 2.9727 1999 -1.66179 2000 4.04473 2001 2.08431 2002 1.92788 2003 2.93213 2004 6.04014 2005 4.60803 2006 5.19192 2007 3.81188 2008 2.47165 2009 -2.54395 2010 4.82324 2011 5.12114 2012 4.3671 2013 3.13202 2014 0.89537 2015 1.44776 2016 0.43428 2017 0.67498