Year	Percent
1991	72.683
1992	72.497
1993	72.831
1994	73.18
1995	72.752
1996	74.041
1997	73.871
1998	73.769
1999	73.739
2000	73.445
2001	73.352
2002	73.124
2003	72.986
2004	72.847
2005	72.749
2006	72.515
2007	72.396
2008	72.388
2009	72.196
2010	72.122
2011	72.059
2012	71.984
2013	71.903
2014	71.843
2015	71.753
2016	71.569
2017	71.471
2018	71.398
2019	71.283
2020	71.112
2021	70.891
2022	70.624