Year	Percent
1991	69.259
1992	68.717
1993	65.628
1994	65.167
1995	64.338
1996	62.354
1997	62.37
1998	63.522
1999	61.758
2000	60.414
2001	59.555
2002	59.977
2003	59.432
2004	56.158
2005	56.288
2006	56.299
2007	56.37
2008	56.766
2009	55.382
2010	55.468
2011	57.78
2012	58.413
2013	60.309
2014	52.728
2015	51.659
2016	52.958
2017	52.935
2018	52.878
2019	52.822
2020	52.767
2021	52.711
2022	52.655