Year	Percent
1991	20.251
1992	20.508
1993	20.913
1994	21.37
1995	21.784
1996	21.558
1997	21.309
1998	21.303
1999	21.571
2000	22.033
2001	22.258
2002	22.212
2003	22.385
2004	22.599
2005	22.744
2006	22.745
2007	22.746
2008	22.688
2009	22.59
2010	22.58
2011	20.431
2012	21.578
2013	22.543
2014	23.514
2015	24.466
2016	24.904
2017	25.044
2018	24.679
2019	23.938
2020	23.108
2021	22.82
2022	22.928