Year	Percent
1991	31.246
1992	30.813
1993	31.444
1994	31.599
1995	31.08
1996	26.414
1997	28.465
1998	31.78
1999	31.499
2000	30.729
2001	31.632
2002	30.118
2003	29.531
2004	28.033
2005	29.739
2006	30.163
2007	33.015
2008	33.252
2009	28.588
2010	24.941
2011	25.971
2012	25.416
2013	25.025
2014	26.101
2015	27.155
2016	23.149
2017	24.871
2018	25.1
2019	25.299
2020	25.409
2021	25.438
2022	25.377