Year	Percent
1991	72.874
1992	73.196
1993	73.18
1994	73.027
1995	72.983
1996	72.104
1997	71.941
1998	72.257
1999	72.253
2000	72.4
2001	72.468
2002	72.269
2003	72.244
2004	72.217
2005	72.403
2006	72.513
2007	72.618
2008	72.886
2009	72.95
2010	73.155
2011	73.772
2012	74.294
2013	74.756
2014	75.174
2015	75.438
2016	75.639
2017	75.719
2018	75.712
2019	75.662
2020	75.602
2021	75.501
2022	75.397