Year	Percent
1991	67.384
1992	65.841
1993	65.196
1994	66.39
1995	67.485
1996	67.307
1997	66.904
1998	67.109
1999	67.36
2000	67.644
2001	67.069
2002	67.295
2003	67.478
2004	67.86
2005	68.667
2006	68.932
2007	69.659
2008	69.799
2009	68.214
2010	68.776
2011	68.71
2012	68.085
2013	67.346
2014	66.75
2015	66.858
2016	66.664
2017	66.626
2018	66.584
2019	66.395
2020	66.273
2021	66.102
2022	65.908