Year	Percent
1971	0.95933
1972	1.08913
1973	1.12694
1974	1.0746
1990	0.97989
1992	0.99428
1993	0.99613
1999	0.99862
2000	0.99725
2001	1.0027
2002	0.97714
2003	0.95992
2004	0.93729
2005	0.93177
2006	0.94206
2007	0.94593
2008	0.95901
2009	0.97358
2010	0.97272
2011	0.97059
2012	0.97759
2013	0.97994
2014	0.98148
2015	0.98491
2016	0.99162