Year	%
1986	75.28521
1987	76.25095
1988	74.77526
1989	75.62241
1990	77.75084
1991	79.36823
1992	81.31739
1993	81.15688
1994	82.8236
1995	85.387
1996	86.04102
1997	86.03985
1998	86.12161
1999	86.83022
2000	87.00303
2001	88.45201
2002	87.90091
2003	88.9931
2004	89.08008
2005	89.84732
2006	90.88185
2007	90.8236
2008	90.83663
2010	90.35119
2011	90.92487
2012	89.88292
2013	89.62725
2014	89.85397
2015	90.49619
2016	90.24544
2017	90.71131