Year	Percent
1991	21.972
1992	22.327
1993	21.2
1994	24.087
1995	24.398
1996	25.168
1997	23.994
1998	24.852
1999	25.211
2000	26.959
2001	25.125
2002	26.624
2003	26.208
2004	27.557
2005	27.201
2006	26.804
2007	27.434
2008	28.424
2009	26.929
2010	26.934
2011	26.126
2012	25.6
2013	26.321
2014	26.399
2015	26.232
2016	24.781
2017	22.898
2018	23.033
2019	23.064
2020	23.096
2021	23.087
2022	23.121