Year	Percent
1991	72.909
1992	72.908
1993	72.928
1994	72.959
1995	72.996
1996	72.825
1997	72.746
1998	72.764
1999	72.89
2000	73.046
2001	73.065
2002	73.195
2003	73.357
2004	73.586
2005	73.855
2006	73.896
2007	73.954
2008	74.084
2009	74.303
2010	74.425
2011	74.474
2012	74.553
2013	74.654
2014	74.762
2015	74.871
2016	74.876
2017	74.817
2018	74.785
2019	74.767
2020	74.754
2021	74.642
2022	74.539