Year	Percent
1991	60.325
1992	60.881
1993	60.27
1994	62.981
1995	64.642
1996	66.286
1997	67.443
1998	69.251
1999	69.468
2000	69.656
2001	69.109
2002	68.749
2003	68
2004	69.224
2005	69.486
2006	68.773
2007	69.36
2008	68.536
2009	66.428
2010	65.048
2011	64.659
2012	63.483
2013	63.605
2014	61.022
2015	61.458
2016	63.904
2017	63.542
2018	63.256
2019	62.916
2020	62.586
2021	62.315
2022	62.041