Year	Percent (Units)
1980	0.566
1981	0.589
1982	0.631
1983	0.658
1984	0.655
1985	0.687
1986	0.707
1987	0.720
1988	0.734
1989	0.742
1990	0.746
1991	0.765
1992	0.741
1993	0.742
1994	0.752
1995	0.762
1996	0.782
1997	0.765
1998	0.770
1999	0.775
2000	0.769
2001	0.778
2002	0.776
2003	0.784
2004	0.802
2005	0.828
2006	0.831
2007	0.830
2008	0.842
2009	0.854
2010	0.830
2011	0.825
2012	0.831
2013	0.829
2014	0.837
2015	0.862
2016	0.868
2017	0.863
2018	0.884
2019	0.887
2020	0.905
2021	0.899
2022	0.924
2023	0.895
2024	0.885
2025	0.887
2026	0.899
2027	0.915
2028	0.933
2029	0.950