Year	Percent
1971	1.05055
1972	0.99422
1973	0.99703
1974	0.99963
1975	1.00809
1976	1.00225
1977	1.00384
1978	1.0128
1979	1.01877
1980	1.01855
1981	1.02609
1982	1.03224
1983	1.02374
1984	1.03453
1985	1.03106
1986	1.02852
1987	1.02951
1988	1.02694
1989	1.02925
1990	1.02295
1991	1.01736
1992	1.00797
1993	0.98824
1994	0.98539
1995	0.97235
1996	0.97238
1997	0.9809
1998	1.00296
1999	1.01015
2000	1.01295
2001	1.0114
2002	1.01104
2003	1.00979
2004	1.01471
2005	1.00623
2006	1.00148
2007	0.99441
2008	0.99043
2009	0.98986
2010	0.99307
2011	0.99462
2012	0.99431
2013	0.98336
2014	0.98209
2015	0.98253
2016	0.98371
