Year	Percent
1991	73.218
1992	74.739
1993	77.384
1994	79.206
1995	80.377
1996	80.637
1997	81.343
1998	76.099
1999	74.445
2000	73.09
2001	72.31
2002	72.431
2003	73.095
2004	74.237
2005	74.062
2006	73.406
2007	73.279
2008	72.818
2009	72.564
2010	72.079
2011	71.285
2012	70.749
2013	70.092
2014	69.806
2015	70.159
2016	70.203
2017	70.103
2018	70.028
2019	69.947
2020	69.862
2021	69.773
2022	69.689