Year	Percent
1971	0.79681
1972	0.81792
1976	0.86176
1977	0.85667
1978	0.86707
1986	0.90612
1987	0.90195
1988	0.90786
1989	0.91515
1990	0.92337
1991	0.94185
1992	0.94596
1993	0.9454
1994	0.9513
1999	0.97051
2000	0.99619
2001	0.9641
2002	0.96755
2003	0.97057
2004	0.96915
2005	0.98933
2006	0.98497
2009	0.99433
2010	1.01098
2014	0.99197
2017	1.02038