Year	Percent
1991	55.287
1992	55.518
1993	54.271
1994	52.694
1995	52.935
1996	53.33
1997	54.917
1998	55.61
1999	56.461
2000	57.06
2001	56.946
2002	57.685
2003	56.182
2004	57.094
2005	57.306
2006	58.382
2007	58.285
2008	58.78
2009	57.39
2010	55.939
2011	55.18
2012	54.644
2013	54.325
2014	54.053
2015	53.99
2016	55.375
2017	55.669
2018	55.804
2019	55.712
2020	55.633
2021	55.541
2022	55.426