Year	Percent
1991	76.526
1992	76.781
1993	76.478
1994	76.182
1995	75.895
1996	75.588
1997	75.286
1998	74.997
1999	74.725
2000	74.462
2001	74.255
2002	74.069
2003	74.213
2004	74.582
2005	74.944
2006	74.572
2007	74.197
2008	73.82
2009	73.454
2010	73.538
2011	73.633
2012	73.827
2013	74.769
2014	74.483
2015	74.15
2016	73.817
2017	73.824
2018	73.833
2019	73.848
2020	73.871
2021	73.899
2022	73.934