Year Percent 1960 6.35665 1961 3.34479 1962 2.7691 1963 2.5275 1964 2.56297 1965 2.43005 1966 2.48619 1967 2.20868 1968 1.72453 1969 1.50453 1970 1.55456 1971 1.83413 1972 1.85221 1973 1.8687 1974 1.66414 1975 1.46027 1976 1.34772 1977 1.38572 1978 1.2097 1979 1.26239 1980 1.26923 1981 4.80769 1982 4.38859 1983 1.29874 1984 1.89022 1985 0.13665 1986 -0.09449 1987 1.50383 1988 2.53777 1989 2.93574 1990 3.88909 1991 2.84548 1992 3.00426 1993 2.52981 1994 3.13659 1995 3.03781 1996 4.06432 1997 3.35744 1998 3.39721 1999 0.79915 2000 1.73204 2001 2.69736 2002 0.91264 2003 -1.47453 2004 1.25192 2005 2.35051 2006 3.12939 2007 4.166 2008 5.32152 2009 3.01595 2010 1.77183 2011 2.0849 2012 2.45339 2013 1.61931 2014 1.29844 2015 1.18638 2016 1.29744 2017 0.0886