Year	Percent
1991	56.748
1992	55.832
1993	55.315
1994	56.602
1995	57.542
1996	57.556
1997	58.141
1998	57.977
1999	58.208
2000	59.137
2001	58.49
2002	59.147
2003	59.75
2004	59.683
2005	58.469
2006	59.957
2007	62.419
2008	62.725
2009	62.997
2010	63.335
2011	63.576
2012	63.965
2013	63.865
2014	64.04
2015	63.966
2016	63.587
2017	64.631
2018	65.064
2019	65.659
2020	66.228
2021	66.77
2022	67.326