Year	Percent (Units)
1980	0.376
1981	0.389
1982	0.400
1983	0.408
1984	0.407
1985	0.408
1986	0.410
1987	0.407
1988	0.398
1989	0.401
1990	0.403
1991	0.410
1992	0.387
1993	0.396
1994	0.402
1995	0.406
1996	0.409
1997	0.412
1998	0.420
1999	0.426
2000	0.428
2001	0.436
2002	0.443
2003	0.447
2004	0.449
2005	0.457
2006	0.465
2007	0.470
2008	0.482
2009	0.510
2010	0.513
2011	0.526
2012	0.562
2013	0.576
2014	0.604
2015	0.636
2016	0.663
2017	0.680
2018	0.707
2019	0.726
2020	0.787
2021	0.791
2022	0.816
2023	0.839
2024	0.872
2025	0.906
2026	0.940
2027	0.974
2028	1.010
2029	1.047