Year	Percent
1991	52.487
1992	52.461
1993	52.289
1994	52.242
1995	52.299
1996	52.152
1997	52.168
1998	52.257
1999	52.372
2000	52.831
2001	53.264
2002	53.673
2003	54.068
2004	54.469
2005	54.901
2006	55.294
2007	55.732
2008	56.192
2009	56.627
2010	56.866
2011	57.455
2012	57.762
2013	58.047
2014	58.226
2015	58.338
2016	58.355
2017	58.136
2018	57.869
2019	57.57
2020	57.251
2021	56.867
2022	56.475