Year	Percent
1991	21.273
1992	23.671
1993	25.258
1994	24.632
1995	23.839
1996	21.913
1997	21.945
1998	20.981
1999	18.904
2000	18.214
2001	17.532
2002	16.992
2003	17.377
2004	17.991
2005	18.465
2006	18.112
2007	21.178
2008	20.401
2009	20.379
2010	24.468
2011	25.518
2012	25.295
2013	24.95
2014	24.363
2015	24.25
2016	24.152
2017	24.259
2018	24.478
2019	24.66
2020	24.843
2021	25.019
2022	25.193