Year	Percent
1991	67.578
1992	66.958
1993	64.319
1994	60.682
1995	59.671
1996	58.705
1997	56.409
1998	58.566
1999	49.987
2000	47.834
2001	50.6
2002	49.305
2003	52.734
2004	56.107
2005	57.589
2006	56.194
2007	56.263
2008	55.017
2009	54.108
2010	56.293
2011	50.795
2012	48.818
2013	51.505
2014	56.571
2015	57.456
2016	59.486
2017	59.259
2018	58.678
2019	58.184
2020	57.861
2021	57.583
2022	57.335