Year	Percent
1960	3.16246
1961	2.87621
1962	3.03854
1963	3.00953
1964	3.00138
1965	2.89294
1966	2.88647
1967	2.49356
1968	2.29478
1969	2.02591
1970	2.05162
1971	2.07126
1972	1.43885
1973	1.53606
1974	1.63457
1975	1.7331
1976	1.17966
1977	1.2281
1978	1.05646
1979	1.05058
1980	1.34613
1981	1.30533
1982	1.41929
1983	1.21479
1984	1.17194
1985	1.13791
1986	1.19852
1987	1.33791
1988	1.3172
1989	1.80972
1990	1.51971
1991	1.41011
1992	1.57529
1993	1.4384
1994	1.30026
1995	1.16474
1996	1.43186
1997	1.5548
1998	1.35459
1999	1.30764
2000	1.35594
2001	1.42638
2002	0.99482
2003	1.09507
2004	1.09953
2005	1.08205
2006	0.91035
2007	1.19774
2008	1.30832
2009	1.36798
2010	1.33537
2011	1.18387
2012	1.23089
2013	1.2002
2014	1.13285
2015	0.88324
2016	1.24909
2017	1.27696