Year	Percent
1991	58.881
1992	59.004
1993	58.984
1994	58.85
1995	58.563
1996	57.912
1997	56.914
1998	56.359
1999	55.744
2000	55.091
2001	54.672
2002	54.27
2003	53.875
2004	53.574
2005	53.368
2006	52.926
2007	48.457
2008	48.242
2009	48.172
2010	48.178
2011	48.353
2012	48.581
2013	48.833
2014	49.12
2015	49.425
2016	49.61
2017	49.778
2018	49.896
2019	49.984
2020	50.062
2021	50.126
2022	50.153