Year	Percent
1991	87.375
1992	88.033
1993	88.195
1994	87.911
1995	87.497
1996	86.659
1997	86.562
1998	86.692
1999	86.998
2000	87.355
2001	88.834
2002	88.706
2003	89.277
2004	89.31
2005	89.836
2006	89.731
2007	89.876
2008	90.834
2009	91.342
2010	91.432
2011	91.52
2012	91.322
2013	91.264
2014	91.891
2015	92.065
2016	92.043
2017	92.116
2018	92.275
2019	92.36
2020	92.42
2021	92.486
2022	92.549