Year	%
1985	74.5873
1986	74.76723
1987	75.602
1988	74.2485
1989	75.09727
1990	77.3435
1991	79.06966
1992	81.12851
1993	81.07631
1994	82.75285
1995	85.47299
1996	86.11328
1997	86.18356
1998	86.19063
1999	87.1111
2000	87.43994
2001	89.00828
2002	89.28041
2003	89.43195
2004	89.36159
2005	90.43087
2006	91.54922
2007	91.71728
2008	92.10309
2009	92.07563
2010	92.02917
2011	92.24882
2012	91.34302
2013	91.08494
2014	91.4571
2015	92.03519
2016	91.86057
2017	92.49461