Year	Percent
1991	71.577
1992	72.572
1993	72.348
1994	71.181
1995	71.728
1996	74.867
1997	75.947
1998	76.159
1999	74.076
2000	74.5
2001	74.879
2002	74.785
2003	76.682
2004	75.768
2005	75.365
2006	75.189
2007	74.485
2008	75.057
2009	74.42
2010	73.982
2011	73.844
2012	73.217
2013	72.857
2014	69.444
2015	69.116
2016	69.098
2017	69.214
2018	69.167
2019	69.116
2020	69.062
2021	69.007
2022	68.951