Year	Percent
1991	74.172
1992	74.436
1993	74.139
1994	74.434
1995	74.213
1996	74.254
1997	74.389
1998	74.556
1999	74.761
2000	75.005
2001	75.202
2002	75.276
2003	75.339
2004	75.497
2005	75.726
2006	76.042
2007	76.321
2008	76.724
2009	77.088
2010	77.48
2011	77.905
2012	78.325
2013	78.633
2014	78.221
2015	77.956
2016	77.595
2017	77.863
2018	78.123
2019	78.369
2020	78.596
2021	78.806
2022	78.998