Year Percent 1960 4.45099 1961 2.96304 1962 4.23649 1963 3.44067 1964 2.41727 1965 2.6274 1966 0.88548 1967 2.5271 1968 2.12353 1969 1.59657 1970 2.43144 1971 2.15642 1972 1.91709 1973 2.8214 1974 3.16058 1975 1.89611 1976 1.2562 1977 1.44371 1978 1.81171 1979 5.46545 1980 2.67008 1981 2.34823 1982 1.5525 1983 1.51941 1984 0.98297 1985 1.07426 1986 1.24583 1987 1.00675 1988 0.84047 1989 1.03591 1990 0.32132 1991 0.82923 1992 0.83965 1993 1.71777 1994 2.25203 1995 1.98013 1996 4.43861 1997 0.83251 1998 0.83481 1999 0.95513 2000 0.88159 2001 0.73696 2002 0.44285 2003 -0.1974 2004 0.77992 2005 0.43687 2006 0.64227 2007 0.85963 2008 0.59824 2009 0.21535 2010 0.73445 2011 0.67254 2012 1.10396 2013 0.40198 2014 0.70237 2015 0.8512 2016 0.61937 2017 0.74822