Year	Percent
1991	57.843
1992	57.041
1993	55.895
1994	55.379
1995	54.835
1996	55.524
1997	55.575
1998	54.724
1999	54.572
2000	54.97
2001	53.286
2002	52.538
2003	51.731
2004	51.656
2005	49.836
2006	58.908
2007	64.425
2008	68.747
2009	67.419
2010	67.106
2011	67.348
2012	66.786
2013	66.695
2014	64.844
2015	62.402
2016	60.242
2017	56.296
2018	56.459
2019	56.551
2020	56.691
2021	56.826
2022	56.976