Year	Percent
1991	81.1
1992	81.816
1993	82.13
1994	81.893
1995	82.164
1996	82.522
1997	83.906
1998	84.257
1999	84.806
2000	85.707
2001	86.118
2002	86.464
2003	87.004
2004	87.051
2005	87.341
2006	87.576
2007	87.476
2008	87.135
2009	86.464
2010	86.854
2011	87.123
2012	87.424
2013	87.703
2014	87.758
2015	88.144
2016	88.183
2017	88.015
2018	88.185
2019	88.345
2020	88.478
2021	88.617
2022	88.75