Year	Percent
1990	69.344
1991	69.645
1992	69.849
1993	69.936
1994	69.924
1995	69.69
1996	69.77
1997	69.722
1998	69.594
1999	69.372
2000	69.13
2001	69.068
2002	68.902
2003	68.785
2004	68.607
2005	68.395
2006	68.299
2007	68.173
2008	67.936
2009	67.817
2010	67.625
2011	67.455
2012	67.24
2013	67.036
2014	66.867
2015	66.706
2016	66.429
2017	66.382
2018	66.341
2019	66.306
2020	66.276
2021	66.247
2022	66.224
2023	66.208
2024	66.2
2025	66.202
2026	66.204
2027	66.215
2028	66.233
2029	66.257
2030	66.286