Year	Percent
1991	70.029
1992	69.73
1993	69.729
1994	69.707
1995	70.531
1996	70.653
1997	70.004
1998	69.951
1999	70.29
2000	69.971
2001	69.911
2002	69.568
2003	70.166
2004	70.546
2005	70.26
2006	69.352
2007	68.964
2008	69.682
2009	69.597
2010	69.712
2011	68.089
2012	68.354
2013	67.826
2014	66.801
2015	66.902
2016	65.907
2017	65.902
2018	65.849
2019	65.793
2020	65.735
2021	65.679
2022	65.62