Year	Percent
1980	0.807
1981	0.791
1982	0.793
1983	0.776
1984	0.762
1985	0.748
1986	0.735
1987	0.724
1988	0.726
1989	0.725
1990	0.718
1991	0.714
1992	0.651
1993	0.632
1994	0.634
1995	0.626
1996	0.613
1997	0.611
1998	0.606
1999	0.607
2000	0.6
2001	0.591
2002	0.584
2003	0.566
2004	0.557
2005	0.543
2006	0.528
2007	0.518
2008	0.508
2009	0.498
2010	0.486
2011	0.475
2012	0.462
2013	0.448
2014	0.438
2015	0.431
2016	0.424
2017	0.416
2018	0.407
2019	0.4
2020	0.391
2021	0.383
2022	0.376
2023	0.368
2024	0.361