Year Percent 1960 3.06201 1961 3.77625 1962 3.37774 1963 3.38344 1964 3.32481 1965 3.07802 1966 3.13685 1967 3.01221 1968 2.94541 1969 2.67822 1970 2.22395 1971 2.08626 1972 2.15703 1973 2.10197 1974 2.19837 1975 2.1025 1976 1.99372 1977 1.92263 1978 1.82902 1979 1.84404 1980 1.82447 1981 1.87321 1982 1.97452 1983 2.07968 1984 2.01433 1985 1.86936 1986 1.89163 1987 1.90236 1988 1.76496 1989 2.09018 1990 1.92448 1991 1.63531 1992 1.15382 1993 0.02879 1994 -0.03543 1995 0.9983 1996 1.48009 1997 1.4585 1998 1.53404 1999 1.48607 2000 1.19113 2001 0.94886 2002 0.9179 2003 1.04844 2004 1.21011 2005 1.12786 2006 1.07505 2007 0.95359 2008 0.95022 2009 1.20727 2010 1.19286 2011 1.21689 2012 1.66524 2013 1.98474 2014 2.00611 2015 2.05903 2016 2.03722 2017 1.98687