Year	Percent
1991	62.274
1992	61.454
1993	60.515
1994	58.878
1995	58.524
1996	58.612
1997	59.05
1998	58.991
1999	56.007
2000	54.28
2001	53.012
2002	50.842
2003	50.553
2004	50.735
2005	52.569
2006	54.292
2007	56.7
2008	59.032
2009	58.842
2010	58.271
2011	58.676
2012	58.634
2013	58.588
2014	59.688
2015	60.313
2016	61.437
2017	61.937
2018	61.948
2019	61.555
2020	61.204
2021	60.758
2022	60.279