Year	Percent
1991	30.765
1992	27.46
1993	29.108
1994	31.264
1995	31.886
1996	28.804
1997	28.536
1998	28.575
1999	25.656
2000	30.887
2001	28.856
2002	29.407
2003	32.534
2004	32.095
2005	31.952
2006	31.489
2007	34.148
2008	32.141
2009	32.8
2010	30.099
2011	27.444
2012	28.748
2013	27.583
2014	25.714
2015	29.013
2016	30.7
2017	31.117
2018	30.343
2019	29.579
2020	28.817
2021	28.05
2022	27.28