Year	Percent
1991	71.017
1992	70.827
1993	70.603
1994	70.33
1995	69.846
1996	69.646
1997	69.314
1998	68.834
1999	68.311
2000	67.867
2001	67.562
2002	67.347
2003	66.435
2004	65.55
2005	64.705
2006	64.097
2007	64.106
2008	64.098
2009	64.087
2010	64.078
2011	64.03
2012	64.665
2013	65.293
2014	65.878
2015	66.491
2016	66.485
2017	66.552
2018	66.602
2019	66.632
2020	66.858
2021	67.013
2022	67.123