Year	Percent
1990	0.87432
1991	0.84693
1992	0.82037
1993	0.79503
1994	0.60009
1995	0.72525
1996	0.70525
1997	0.68506
1998	0.65453
1999	0.63834
2000	0.56382
2001	0.55641
2002	0.52815
2003	0.62972
2004	0.59384
2005	0.61065
2006	0.59457
2007	0.58458
2008	0.5749
2009	0.55422
2010	0.54529
2011	0.53593
2012	0.52727
2013	0.51877
2014	0.51003
2015	0.50087
2016	0.44122
2017	0.47629
2018	0.42189
2019	0.40607
2020	0.39725