Year	Percent
1991	65.726
1992	66.54
1993	67.879
1994	68.485
1995	68.491
1996	69.673
1997	70.234
1998	69.573
1999	70.268
2000	70.923
2001	71.56
2002	72.171
2003	72.255
2004	72.585
2005	72.875
2006	72.991
2007	72.249
2008	72.695
2009	73.042
2010	72.267
2011	72.721
2012	73
2013	72.725
2014	72.981
2015	73.569
2016	73.902
2017	73.1
2018	73.564
2019	73.876
2020	74.12
2021	74.372
2022	74.62