Year	Percent
1991	72.448
1992	72.297
1993	71.399
1994	71.064
1995	70.544
1996	68.959
1997	68.67
1998	68.178
1999	67.262
2000	66.788
2001	64.682
2002	63.807
2003	63.533
2004	64.195
2005	64.425
2006	64.501
2007	64.404
2008	63.986
2009	61.896
2010	62.527
2011	63.57
2012	64.009
2013	63.914
2014	64.049
2015	64.337
2016	63.796
2017	63.528
2018	63.16
2019	62.621
2020	62.215
2021	61.823
2022	61.451