Year	%
1989	73.14778
1990	75.26375
1991	76.71911
1992	78.73755
1993	78.62542
1994	80.33701
1995	82.98346
1996	83.74116
1997	83.96672
1998	84.19351
1999	85.07507
2000	85.72109
2001	87.24333
2002	88.42894
2003	87.56301
2004	87.59518
2005	88.78774
2006	89.91406
2007	90.39204
2008	90.35695
2010	90.80524
2011	90.72686
2012	89.47757
2013	89.35678
2014	89.51717
2015	90.10476
2016	89.7389
2017	90.27533