Year	Percent
1991	65.393
1992	64.73
1993	65.377
1994	66.997
1995	69.114
1996	69.46
1997	68.867
1998	67.46
1999	67.744
2000	68.637
2001	69.549
2002	70.469
2003	70.196
2004	71.514
2005	72.094
2006	72.595
2007	72.771
2008	71.815
2009	69.753
2010	69.448
2011	69.662
2012	68.893
2013	69.606
2014	70.681
2015	70.481
2016	71.428
2017	71.463
2018	71.227
2019	70.969
2020	70.834
2021	70.674
2022	70.475