Year	%
1985	73.99814
1986	74.23085
1987	75.08139
1988	73.82478
1989	74.69463
1990	76.80783
1991	78.34226
1992	80.31652
1993	80.17615
1994	81.81309
1995	84.4146
1996	85.11803
1997	85.14616
1998	85.34312
1999	86.1182
2000	86.49346
2001	87.96055
2002	88.20686
2003	88.37464
2004	88.43923
2005	89.41403
2006	90.48457
2007	90.68121
2008	90.66086
2009	90.59903
2010	90.60431
2011	90.87156
2012	89.74144
2013	89.54977
2014	89.73628
2015	90.34765
2016	90.04416
2017	90.54258