Year	Percent
1991	22.376
1992	22.943
1993	22.951
1994	21.995
1995	21.562
1996	20.867
1997	20.966
1998	20.821
1999	20.907
2000	24.742
2001	24.848
2002	24.829
2003	24.693
2004	24.659
2005	24.554
2006	24.661
2007	24.509
2008	24.157
2009	24.347
2010	24.273
2011	24.493
2012	24.553
2013	24.788
2014	24.532
2015	24.608
2016	24.651
2017	25.064
2018	25.226
2019	25.369
2020	25.625
2021	25.946
2022	26.276