Year	Percent
1991	81.302
1992	81.712
1993	82.824
1994	82.359
1995	82.529
1996	82.853
1997	83.876
1998	83.569
1999	83.161
2000	84.643
2001	83.889
2002	86.118
2003	86.595
2004	86.122
2005	85.988
2006	86.908
2007	85.784
2008	86.667
2009	88.83
2010	89.928
2011	89.77
2012	89.436
2013	89.831
2014	89.815
2015	89.275
2016	89.658
2017	89.442
2018	89.615
2019	89.778
2020	89.922
2021	90.076
2022	90.201
