Year	Percent
1991	64.825
1992	59.587
1993	55.787
1994	55.015
1995	53.702
1996	54.063
1997	55.875
1998	57.101
1999	58.57
2000	59.353
2001	59.693
2002	59.018
2003	58.613
2004	58.451
2005	59.528
2006	60.389
2007	61.091
2008	61.828
2009	58.356
2010	58.061
2011	58.658
2012	58.304
2013	57.24
2014	56.58
2015	56.133
2016	56.532
2017	56.397
2018	56.426
2019	56.313
2020	56.11
2021	55.855
2022	55.599