Year	Percent
1971	0.95122
1972	0.99457
1977	1.00906
1978	1.00719
1979	1.00707
1980	1.00802
1981	1.07185
1982	1.08528
1983	1.06394
1984	1.02517
1985	1.02155
1986	0.93889
1988	0.96037
1993	1.04313
2002	1.03268
2003	0.98662
2004	1.01308
2005	0.99316
2007	0.97915
2008	0.93032
2009	0.96781
2010	0.99481
2013	0.96866
2014	0.98764
2015	0.97707
2016	0.99446