Year	%
1970	66.27148
1971	72.77356
1972	80.17818
1973	80.50139
1974	81.00045
1990	89.27361
1992	91.87878
1993	91.07161
1994	91.91704
1995	92.29007
1996	92.69576
1997	93.30519
1998	94.39323
1999	94.84276
2000	95.01938
2001	96.15563
2002	95.67508
2003	95.08023
2004	95.08264
2005	95.09899
2006	95.30136
2007	95.19739
2008	95.68595
2009	95.50661
2010	95.59049
2011	95.44683
2012	95.6226
2013	95.68875
2014	95.49656
2015	95.61019
2016	95.7617
2017	95.9458