Year	Percent
1991	63.878
1992	63.922
1993	61.811
1994	62.3
1995	60.912
1996	58.411
1997	56.714
1998	57.254
1999	59.21
2000	56.732
2001	55.76
2002	56.09
2003	54.851
2004	52.86
2005	54.774
2006	55.907
2007	57.168
2008	57.668
2009	55.863
2010	56.609
2011	57.945
2012	57.043
2013	56.428
2014	54.345
2015	54.062
2016	53.037
2017	53.927
2018	53.984
2019	53.873
2020	53.812
2021	53.774
2022	53.79