Year	Percent
1991	75.529
1992	75.607
1993	76.59
1994	75.98
1995	75.574
1996	75.502
1997	74.992
1998	74.988
1999	74.899
2000	76.049
2001	76.145
2002	78.975
2003	78.848
2004	78.877
2005	78.622
2006	78.471
2007	78.499
2008	78.425
2009	78.213
2010	78.386
2011	77.839
2012	77.019
2013	76.668
2014	76.201
2015	76.335
2016	76.635
2017	76.795
2018	76.88
2019	76.966
2020	77.049
2021	77.128
2022	77.197