Year	Percent
1991	59.9
1992	59.346
1993	59.4
1994	59.473
1995	58.744
1996	59.417
1997	59.087
1998	58.904
1999	56.07
2000	55.483
2001	55.075
2002	55.023
2003	54.703
2004	55.084
2005	54.874
2006	54.8
2007	54.194
2008	53.561
2009	53.68
2010	53.343
2011	50.807
2012	50.288
2013	49.275
2014	48.639
2015	49.146
2016	48.671
2017	50.634
2018	49.852
2019	49.034
2020	48.308
2021	47.562
2022	46.687