Year	%
1985	73.8657
1986	74.04976
1987	75.45044
1988	72.43595
1989	73.24292
1990	73.95592
1991	75.21276
1992	76.19401
1993	77.1679
1994	78.19396
1995	79.11411
1996	80.13856
1997	81.07249
1998	82.02348
1999	82.90272
2000	82.93916
2001	85.30147
2002	86.88617
2003	84.1031
2004	83.86803
2005	85.81752
2006	87.14446
2007	87.32079
2008	87.76043
2009	88.56863
2010	88.97157
2011	89.13566
2012	87.87041
2013	88.18172
2014	87.94403
2015	88.98887
2016	88.41135
2017	89.41469