Year	Percent (Units)
1980	0.459
1981	0.482
1982	0.503
1983	0.535
1984	0.564
1985	0.571
1986	0.615
1987	0.668
1988	0.691
1989	0.724
1990	0.735
1991	0.777
1992	0.758
1993	0.794
1994	0.829
1995	0.852
1996	0.870
1997	0.887
1998	0.899
1999	0.928
2000	0.941
2001	0.906
2002	0.930
2003	0.931
2004	0.946
2005	0.952
2006	0.957
2007	0.971
2008	0.951
2009	0.940
2010	0.984
2011	0.982
2012	0.964
2013	0.959
2014	0.970
2015	0.982
2016	0.955
2017	0.932
2018	0.925
2019	0.927
2020	0.987
2021	0.989
2022	0.982
2023	0.966
2024	0.965
2025	0.961
2026	0.955
2027	0.949
2028	0.942
2029	0.933