Year	%
1985	76.29209
1986	76.37883
1987	77.28819
1988	75.73581
1989	76.79377
1990	79.37542
1991	81.20418
1992	83.69079
1993	83.61683
1994	85.39838
1995	88.47201
1996	89.18002
1997	89.10606
1998	89.04321
1999	90.01218
2000	90.23153
2001	91.67273
2002	91.78614
2003	91.80708
2004	91.78411
2005	92.97725
2006	94.17381
2007	94.29775
2008	94.56419
2009	94.46505
2010	94.62127
2011	94.67163
2012	93.84856
2013	93.25793
2014	93.766
2015	94.23761
2016	94.24575
2017	94.95672