Year	Percent
1991	90.625
1992	90.5
1993	90.532
1994	90.801
1995	90.305
1996	90.052
1997	89.32
1998	88.999
1999	87.965
2000	87.701
2001	87.51
2002	87.041
2003	85.702
2004	84.55
2005	84.19
2006	83.059
2007	77.185
2008	72.927
2009	65.867
2010	58.721
2011	50.313
2012	41.532
2013	32.793
2014	22.082
2015	20.862
2016	20.436
2017	19.832
2018	19.242
2019	18.696
2020	18.149
2021	17.604
2022	17.034