Year	Percent
1960	2.26244
1961	2.39012
1962	2.31698
1963	2.44528
1964	2.51908
1965	2.60206
1966	2.66668
1967	2.77023
1968	2.73015
1969	2.58057
1970	2.37937
1971	2.14472
1972	1.93729
1973	1.84288
1974	1.83564
1975	1.94348
1976	2.08631
1977	2.12554
1978	2.11335
1979	1.92432
1980	1.63315
1981	1.37457
1982	1.10356
1983	0.93845
1984	0.91491
1985	0.90662
1986	0.9748
1987	1.00496
1988	1.04837
1989	1.1044
1990	1.18978
1991	1.24796
1992	1.32755
1993	1.42052
1994	1.47969
1995	1.52949
1996	1.5831
1997	1.6244
1998	1.6108
1999	1.49396
2000	1.34287
2001	1.15
2002	1.02529
2003	0.88676
2004	0.79807
2005	0.73725
2006	0.69481
2007	0.64473
2008	0.6181
2009	0.63108
2010	0.66045
2011	0.72232
2012	0.77189
2013	0.7877
2014	0.79231
2015	0.74064
2016	0.70069
2017	0.67736