Year	Percent
1971	0.92925
1972	0.92645
1973	0.93424
1974	0.93994
1975	0.94065
1976	0.9393
1977	0.94152
1978	0.94806
1979	0.95419
1980	0.97014
1981	0.96639
1982	0.96013
1983	0.95735
1984	0.95192
1985	0.96217
1986	0.9647
1987	0.9726
1988	0.9918
1989	0.99503
1990	1.00405
1996	1.01572
1998	1.00517
1999	0.99263
2000	0.98093
2001	0.98546
2002	0.99862
2003	0.99496
2004	0.98954
2005	0.98692
2006	1.01417
2007	1.01478
2008	1.0149
2009	1.02297
2010	1.02582
2011	1.0276
2012	1.02841
2013	1.02307
2014	1.01929
2015	1.03202
2016	1.03945