Year	Percent
1991	63.916
1992	64.097
1993	63.484
1994	63.566
1995	60.623
1996	60.999
1997	60.234
1998	60.987
1999	60.126
2000	62.991
2001	62.973
2002	62.409
2003	69.573
2004	70.653
2005	70.75
2006	71.715
2007	72.383
2008	72.564
2009	69.948
2010	68.664
2011	67.284
2012	66.355
2013	65.863
2014	66.399
2015	66.081
2016	65.887
2017	65.685
2018	65.67
2019	65.644
2020	65.611
2021	65.579
2022	65.545