Year	Percent
1991	35.48
1992	39.322
1993	35.703
1994	35.992
1995	25.871
1996	20.739
1997	20.829
1998	21.686
1999	22.423
2000	24.624
2001	25.607
2002	26.209
2003	26.086
2004	27.107
2005	24.111
2006	23.602
2007	23.739
2008	23.034
2009	22.589
2010	22.335
2011	19.371
2012	19.38
2013	20.027
2014	21.742
2015	23.536
2016	24.198
2017	23.823
2018	24.064
2019	24.265
2020	24.512
2021	24.784
2022	25.065