Year	Percent
1991	38.246
1992	36.574
1993	34.789
1994	35.377
1995	33.136
1996	32.422
1997	31.058
1998	31.133
1999	24.734
2000	25.867
2001	22.692
2002	19.416
2003	20.513
2004	24.599
2005	26.652
2006	26.068
2007	30.353
2008	33.706
2009	27.181
2010	24.448
2011	28.998
2012	30.222
2013	30.286
2014	33.049
2015	33.104
2016	36.07
2017	35.5
2018	34.642
2019	33.809
2020	33.127
2021	32.633
2022	32.317