Year	Percent
1991	48.407
1992	48.203
1993	48.531
1994	50.156
1995	51.545
1996	52.878
1997	52.447
1998	51.945
1999	52.725
2000	53.298
2001	54.532
2002	55.173
2003	55.624
2004	56.399
2005	57.609
2006	58.107
2007	58.729
2008	58.848
2009	57.714
2010	57.071
2011	57.668
2012	57.457
2013	58.073
2014	59.076
2015	59.156
2016	60.406
2017	60.501
2018	60.33
2019	60.141
2020	60.068
2021	59.981
2022	59.865