Year	%
1988	66.54685
1989	66.97279
1990	71.26899
1991	73.251
1992	77.07372
1993	76.4374
1994	79.67999
1995	85.655
1996	86.0102
1997	85.09722
1998	84.06688
1999	85.48712
2000	86.88197
2001	88.49749
2002	89.93891
2003	91.24824
2004	91.13815
2005	93.89944
2006	96.28267
2007	96.2909
2008	96.4274
2009	96.04992
2010	95.98247
2011	96.69167
2012	95.15273
2013	93.874
2014	96.04338
2015	96.52171
2016	96.55461
2017	96.60876