Year	%
1983	77.6751
1984	77.48097
1985	77.47046
1986	78.4922
1987	78.44219
1989	79.8942
1990	80.54677
1991	79.78816
1992	80.45268
1993	80.4066
1994	81.70934
1995	82.21308
1996	82.46244
1998	84.05916
2000	85.11071
2001	85.28161
2003	87.36475
2004	87.75909
2005	89.0579
2006	88.30577
2007	89.50257
2008	89.17901
2009	90.1554
2011	90.30138
2016	90.01907
2017	89.94485