Year	Percent
1991	33.673
1992	33.676
1993	33.062
1994	32.736
1995	32.409
1996	32.451
1997	32.314
1998	31.777
1999	31.592
2000	30.619
2001	31.196
2002	30.232
2003	29.076
2004	29.566
2005	30.194
2006	29.893
2007	28.683
2008	28.049
2009	27.315
2010	26.852
2011	26.21
2012	26.302
2013	25.35
2014	24.791
2015	25.201
2016	25.199
2017	25.318
2018	25.151
2019	24.921
2020	24.82
2021	24.697
2022	24.602