Year	Percent
1991	32.284
1992	31.67
1993	30.695
1994	28.776
1995	27.507
1996	27.72
1997	27.513
1998	27.349
1999	27.122
2000	27.079
2001	26.798
2002	26.253
2003	25.928
2004	25.411
2005	25.069
2006	24.629
2007	25.294
2008	27.548
2009	27.768
2010	26.064
2011	25.892
2012	25.349
2013	25.804
2014	24.766
2015	24.727
2016	24.837
2017	24.658
2018	24.467
2019	24.292
2020	24.114
2021	23.934
2022	23.752