Year	Percent
1991	68.859
1992	69.371
1993	69.699
1994	69.095
1995	68.866
1996	69.895
1997	69.566
1998	68.902
1999	67.878
2000	66.467
2001	65.484
2002	64.487
2003	64.181
2004	63.098
2005	64.564
2006	66.371
2007	67.852
2008	69.559
2009	69.787
2010	69.825
2011	69.75
2012	69.128
2013	68.835
2014	69.208
2015	69.414
2016	68.862
2017	68.765
2018	68.818
2019	68.884
2020	68.89
2021	68.887
2022	68.881