Year	Percent
1990	79.2
1991	79.383
1992	79.541
1993	78.685
1994	78.704
1995	78.542
1996	77.821
1997	77.81
1998	77.36
1999	76.748
2000	76.39
2001	75.52
2002	75.1
2003	74.58
2004	74.967
2005	74.925
2006	74.801
2007	74.637
2008	74.494
2009	73.713
2010	73.937
2011	74.431
2012	74.824
2013	74.78
2014	74.912
2015	75.33
2016	75.149
2017	75.114
2018	75.147
2019	75.215
2020	75.297
2021	75.402
2022	75.53
2023	75.652
2024	75.727
2025	75.724
2026	75.647
2027	75.481
2028	75.234
2029	74.933
2030	74.596