Year	Percent
1991	25.446
1992	25.649
1993	24.154
1994	24.044
1995	27.148
1996	28.034
1997	27.245
1998	27.587
1999	25.589
2000	22.589
2001	22.153
2002	22.018
2003	23.934
2004	26.244
2005	25.624
2006	27.832
2007	29.946
2008	33.105
2009	30.763
2010	27.436
2011	24.894
2012	24.647
2013	23.696
2014	23.9
2015	24.294
2016	23.627
2017	24.235
2018	24.236
2019	23.771
2020	23.297
2021	22.947
2022	22.728