Year	Percent
1991	77.99
1992	76.335
1993	74.877
1994	73.894
1995	73.33
1996	72.167
1997	74.223
1998	72.687
1999	74.087
2000	75.499
2001	76.876
2002	75.674
2003	75.734
2004	75.781
2005	75.761
2006	77.023
2007	77.375
2008	77.73
2009	76.824
2010	76.041
2011	75.926
2012	75.709
2013	76.107
2014	76.714
2015	75.601
2016	77.78
2017	76.475
2018	76.706
2019	76.894
2020	77.103
2021	77.278
2022	77.461