Year	Percent
1991	63.668
1992	63.58
1993	63.643
1994	63.533
1995	63.417
1996	63.334
1997	63.216
1998	63.126
1999	63.055
2000	63.012
2001	63.071
2002	63.273
2003	63.206
2004	63.206
2005	64.787
2006	66.419
2007	67.992
2008	69.6
2009	71.263
2010	72.956
2011	74.901
2012	74.937
2013	74.904
2014	74.825
2015	74.709
2016	74.3
2017	73.936
2018	73.592
2019	73.252
2020	72.926
2021	72.611
2022	72.311