Year	Percent
1991	78.088
1992	77.683
1993	77.306
1994	77.369
1995	77.187
1996	76.85
1997	76.681
1998	76.093
1999	75.793
2000	76.062
2001	75.749
2002	75.341
2003	75.365
2004	74.957
2005	74.694
2006	74.585
2007	74.657
2008	74.595
2009	73.827
2010	73.787
2011	73.946
2012	73.16
2013	73.029
2014	72.381
2015	72.231
2016	72.479
2017	72.223
2018	71.816
2019	71.564
2020	71.216
2021	70.835
2022	70.466