Year	Percent
1991	86.198
1992	86.142
1993	86.544
1994	86.524
1995	87.57
1996	88.022
1997	87.751
1998	87.899
1999	87.715
2000	87.574
2001	87.623
2002	87.735
2003	87.785
2004	87.939
2005	87.949
2006	87.938
2007	87.878
2008	88.015
2009	87.992
2010	88.147
2011	88.263
2012	88.313
2013	88.308
2014	88.375
2015	88.445
2016	88.498
2017	88.491
2018	88.508
2019	88.461
2020	88.412
2021	88.359
2022	88.304