Year	Percent
1991	25.176
1992	26.175
1993	26.13
1994	25.583
1995	25.353
1996	25.775
1997	24.87
1998	25.366
1999	26.198
2000	25.722
2001	24.69
2002	24.369
2003	24.57
2004	24.013
2005	22.989
2006	22.08
2007	21.227
2008	21.46
2009	20.611
2010	20.143
2011	20.499
2012	20.48
2013	18.867
2014	18.396
2015	17.744
2016	21.083
2017	20.959
2018	20.699
2019	20.466
2020	20.313
2021	20.181
2022	20.035