Year	Percent
1991	55.795
1992	55.819
1993	56.012
1994	55.193
1995	55.388
1996	55.311
1997	54.957
1998	54.801
1999	55.01
2000	54.596
2001	55.475
2002	56.432
2003	56.335
2004	56.367
2005	56.168
2006	55.688
2007	55.681
2008	55.565
2009	55.848
2010	56.089
2011	55.905
2012	55.467
2013	55.006
2014	54.686
2015	54.921
2016	54.739
2017	54.935
2018	55.265
2019	55.513
2020	55.517
2021	55.248
2022	54.817