Year	%
1986	78.65822
1987	79.36064
1988	78.02166
1989	78.74144
1990	80.59867
1991	81.97291
1992	83.64376
1993	83.45929
1994	84.79596
1995	87.03998
1996	87.61133
1997	87.50401
1998	87.56153
1999	88.1567
2000	88.32428
2001	89.59834
2002	89.11169
2003	90.07434
2004	90.15044
2005	90.83426
2006	91.71657
2007	91.67171
2008	91.65536
2010	91.21799
2011	91.72354
2012	90.84775
2013	90.62181
2014	90.75678
2015	91.30774
2016	91.04049
2017	91.46274