Year	Percent
1991	71.969
1992	71.802
1993	68.585
1994	68.297
1995	67.554
1996	65.788
1997	64.831
1998	64.729
1999	62.482
2000	61.181
2001	60.022
2002	60.636
2003	59.792
2004	56.996
2005	57.217
2006	57.083
2007	57.502
2008	57.363
2009	56.591
2010	56.754
2011	58.614
2012	59.203
2013	59.135
2014	53.337
2015	52.24
2016	53.434
2017	53.412
2018	53.356
2019	53.302
2020	53.248
2021	53.194
2022	53.139