Year	Percent
1980	1.336
1981	1.238
1982	1.196
1983	1.21
1984	1.182
1985	1.062
1986	1.099
1987	1.085
1988	1.018
1989	0.913
1990	0.865
1991	0.934
1992	0.925
1993	0.964
1994	0.991
1995	0.929
1996	0.945
1997	0.981
1998	0.992
1999	0.926
2000	0.877
2001	0.818
2002	0.709
2003	0.742
2004	0.768
2005	0.797
2006	0.818
2007	0.846
2008	0.855
2009	0.808
2010	0.845
2011	0.86
2012	0.825
2013	0.818
2014	0.77
2015	0.766
2016	0.726
2017	0.719
2018	0.677
2019	0.648
2020	0.639
2021	0.637
2022	0.636
2023	0.636
2024	0.636