Year	Percent (Units)
1980	0.557
1981	0.577
1982	0.606
1983	0.625
1984	0.633
1985	0.639
1986	0.652
1987	0.688
1988	0.746
1989	0.807
1990	0.866
1991	0.916
1992	0.901
1993	0.960
1994	1.007
1995	1.051
1996	1.069
1997	0.999
1998	0.898
1999	0.907
2000	0.904
2001	0.913
2002	0.943
2003	0.971
2004	0.980
2005	0.976
2006	0.973
2007	0.974
2008	0.963
2009	0.961
2010	0.981
2011	0.952
2012	1.000
2013	0.991
2014	0.964
2015	0.969
2016	0.984
2017	0.983
2018	0.989
2019	0.983
2020	0.951
2021	0.907
2022	0.900
2023	0.889
2024	0.886
2025	0.883
2026	0.882
2027	0.881
2028	0.880
2029	0.879