Year	Percent
1960	1.96061
1961	1.97727
1962	1.98926
1963	1.99696
1964	2.00022
1965	1.99806
1966	2.00157
1967	2.00043
1968	1.97571
1969	1.92164
1970	1.8527
1971	1.77893
1972	1.72512
1973	1.70981
1974	1.74428
1975	1.81415
1976	1.8864
1977	1.95048
1978	2.0225
1979	2.10081
1980	2.17812
1981	2.25662
1982	2.32042
1983	2.34703
1984	2.32866
1985	2.27925
1986	2.22052
1987	2.16744
1988	2.11786
1989	2.07641
1990	2.04093
1991	2.00324
1992	1.96288
1993	1.92703
1994	1.8968
1995	1.8703
1996	1.84666
1997	1.8212
1998	1.79025
1999	1.75142
2000	1.70826
2001	1.66306
2002	1.62226
2003	1.5925
2004	1.57638
2005	1.56919
2006	1.56437
2007	1.5547
2008	1.53819
2009	1.51186
2010	1.4784
2011	1.44395
2012	1.41095
2013	1.37608
2014	1.33965
2015	1.30239
2016	1.26424
2017	1.2268