Year	Percent
1971	0.96903
1972	0.91778
1973	0.94099
1974	0.92613
1975	0.93214
1976	0.93284
1977	0.93687
1978	0.92283
1979	0.91527
1980	0.92785
1981	0.91627
1982	0.92749
1983	0.92456
1984	0.9353
1985	0.95013
1986	0.95758
1987	0.96003
1988	0.96286
1989	0.9615
1990	0.95338
1991	0.9512
1992	0.94723
1993	0.94986
1994	0.9384
1995	0.94946
1996	1.00076
1997	0.98374
1998	0.99082
1999	0.96716
2000	0.99148
2001	0.97384
2002	0.98659
2003	0.99038
2004	0.96202
2005	0.96688
2006	0.98813
2007	0.97405
2008	0.98085
2010	0.93719
2011	1.00696
2012	1.01516
2013	1.02197
2014	1.03318
2015	1.04877
2016	1.04016