Year	Percent
1991	30.569
1992	29.926
1993	29.214
1994	29.185
1995	33.194
1996	32.358
1997	31.513
1998	32.605
1999	33.324
2000	33.282
2001	33.752
2002	33.902
2003	34.317
2004	33.857
2005	32.233
2006	30.425
2007	29.177
2008	28.203
2009	29.705
2010	28.32
2011	27.659
2012	26.297
2013	26.907
2014	27.255
2015	27.126
2016	28.106
2017	28.095
2018	28.029
2019	27.938
2020	27.856
2021	27.782
2022	27.7