Year	Percent
1991	74.913
1992	74.174
1993	74.614
1994	74.908
1995	74.955
1996	74.716
1997	75.052
1998	75.244
1999	74.648
2000	74.829
2001	74.849
2002	74.461
2003	73.943
2004	74.231
2005	74.037
2006	74.554
2007	74.768
2008	74.694
2009	74.903
2010	74.56
2011	73.851
2012	72.741
2013	72.107
2014	71.939
2015	72.005
2016	71.385
2017	71.972
2018	71.824
2019	71.707
2020	71.284
2021	70.879
2022	70.339