Year	Percent
1991	73.073
1992	74
1993	73.975
1994	73.478
1995	73.639
1996	73.706
1997	73.65
1998	74.347
1999	74.593
2000	74.525
2001	75.174
2002	75.277
2003	74.992
2004	74.685
2005	74.667
2006	74.741
2007	74.665
2008	74.524
2009	73.891
2010	74.028
2011	73.816
2012	73.154
2013	72.496
2014	72.24
2015	72.248
2016	71.981
2017	71.635
2018	71.208
2019	70.689
2020	70.231
2021	69.793
2022	69.313