Year	Percent
1991	67.857
1992	67.616
1993	67.699
1994	66.589
1995	65.184
1996	63.705
1997	62.898
1998	63.157
1999	64.304
2000	64.601
2001	64.046
2002	63.941
2003	65.556
2004	64.221
2005	61.93
2006	61.373
2007	61.56
2008	62.104
2009	61.228
2010	60.187
2011	57.466
2012	54.794
2013	53.601
2014	53.247
2015	50.882
2016	51.105
2017	51.012
2018	50.932
2019	50.85
2020	50.768
2021	50.685
2022	50.603