Year	Percent
1991	81.208
1992	82.121
1993	82.582
1994	79.46
1995	81.727
1996	83.007
1997	83.322
1998	83.631
1999	84.144
2000	85.388
2001	85.881
2002	86.395
2003	86.498
2004	86.796
2005	87.465
2006	87.861
2007	88.174
2008	88.24
2009	88.327
2010	88.038
2011	88.584
2012	89.021
2013	88.796
2014	89.029
2015	89.259
2016	89.77
2017	88.526
2018	88.324
2019	89.17
2020	89.193
2021	89.222
2022	89.251