Year	Percent
1991	82.98
1992	83.4
1993	83.889
1994	83.991
1995	83.818
1996	83.423
1997	81.051
1998	79.087
1999	79.054
2000	78.736
2001	83.493
2002	83.785
2003	84.054
2004	83.828
2005	84.784
2006	85.78
2007	87.132
2008	88.115
2009	88.748
2010	88.921
2011	88.935
2012	88.796
2013	88.486
2014	88.458
2015	88.333
2016	88.208
2017	88.463
2018	88.713
2019	88.93
2020	89.098
2021	89.228
2022	89.319