Year	Percent
1991	74.401
1992	74.301
1993	74.175
1994	73.502
1995	73.717
1996	73.806
1997	73.33
1998	73.008
1999	72.465
2000	72.656
2001	75.034
2002	75.407
2003	75.873
2004	75.043
2005	74.777
2006	74.756
2007	74.543
2008	74.635
2009	74.26
2010	74.359
2011	74.743
2012	74.266
2013	69.501
2014	69.076
2015	68.361
2016	67.604
2017	67.547
2018	67.453
2019	67.363
2020	67.279
2021	67.202
2022	67.126