Year	Percent (Units)
1980	0.687
1981	0.695
1982	0.718
1983	0.714
1984	0.634
1985	0.567
1986	0.567
1987	0.570
1988	0.582
1989	0.596
1990	0.590
1991	0.574
1992	0.519
1993	0.520
1994	0.527
1995	0.532
1996	0.542
1997	0.548
1998	0.530
1999	0.530
2000	0.528
2001	0.531
2002	0.535
2003	0.541
2004	0.547
2005	0.549
2006	0.549
2007	0.555
2008	0.563
2009	0.574
2010	0.585
2011	0.585
2012	0.607
2013	0.618
2014	0.637
2015	0.654
2016	0.686
2017	0.696
2018	0.715
2019	0.738
2020	0.688
2021	0.683
2022	0.711
2023	0.728
2024	0.750
2025	0.771
2026	0.794
2027	0.819
2028	0.845
2029	0.872