Year	Percent
1991	63.228
1992	63.154
1993	63.141
1994	63.183
1995	63.118
1996	62.885
1997	62.696
1998	62.38
1999	61.894
2000	63.572
2001	65.301
2002	67.048
2003	68.724
2004	70.23
2005	71.87
2006	71.847
2007	71.801
2008	71.749
2009	71.69
2010	71.611
2011	71.542
2012	71.501
2013	71.595
2014	71.544
2015	71.493
2016	71.32
2017	71.391
2018	71.479
2019	71.579
2020	71.685
2021	71.801
2022	71.925