Year	Percent
1991	76.268
1992	76.403
1993	76.194
1994	75.272
1995	75.695
1996	73.926
1997	73.027
1998	71.917
1999	71.42
2000	70.856
2001	69.519
2002	69.848
2003	69.621
2004	68.686
2005	67.872
2006	67.349
2007	66.644
2008	66.252
2009	65.783
2010	65.042
2011	63.953
2012	62.999
2013	62.453
2014	61.314
2015	60.389
2016	60.037
2017	60.082
2018	60.118
2019	60.681
2020	60.63
2021	60.715
2022	59.55