Year	Percent
1991	26.305
1992	24.932
1993	23.349
1994	22.544
1995	22.054
1996	21.037
1997	20.52
1998	20.357
1999	19.921
2000	18.972
2001	17.922
2002	17.029
2003	16.558
2004	16.113
2005	15.665
2006	14.429
2007	13.903
2008	13.201
2009	12.758
2010	12.246
2011	11.731
2012	10.779
2013	10.484
2014	10.302
2015	9.8
2016	9.212
2017	9.615
2018	9.178
2019	9.029
2020	8.9
2021	8.806
2022	8.621