Year	Percent
1991	32.037
1992	32.017
1993	31.699
1994	31.22
1995	30.926
1996	30.681
1997	30.179
1998	29.693
1999	29.229
2000	28.574
2001	28.164
2002	27.888
2003	27.41
2004	26.975
2005	26.651
2006	26.339
2007	26.087
2008	26.215
2009	26.921
2010	26.892
2011	26.706
2012	26.67
2013	26.511
2014	26.223
2015	26.009
2016	25.872
2017	25.856
2018	25.769
2019	25.636
2020	25.44
2021	25.217
2022	24.992