Year	Percent
1991	76.292
1992	76.03
1993	76.08
1994	76.636
1995	76.269
1996	76.34
1997	77.385
1998	78.445
1999	80.476
2000	80.05
2001	79.525
2002	78.754
2003	78.273
2004	77.625
2005	76.856
2006	76.265
2007	75.681
2008	75.072
2009	73.99
2010	72.954
2011	72.076
2012	71.364
2013	70.412
2014	70.49
2015	69.702
2016	69.348
2017	69.895
2018	69.845
2019	69.782
2020	69.7
2021	69.598
2022	69.47