Year	Percent
1991	19.673
1992	17.878
1993	16.667
1994	16.362
1995	16.192
1996	16.239
1997	16.216
1998	16.471
1999	16.319
2000	16.633
2001	16.576
2002	16.905
2003	17.377
2004	18.142
2005	18.111
2006	19.355
2007	20.726
2008	21.909
2009	21.736
2010	21.14
2011	21.193
2012	21.173
2013	22.582
2014	24.217
2015	25.164
2016	25.013
2017	24.335
2018	24.677
2019	25.255
2020	25.494
2021	25.845
2022	26.248