Year	Percent
1990	0.68508
1991	0.66741
1992	0.65114
1993	0.63587
1994	0.62112
1995	0.87245
1996	0.85179
1997	0.83016
1998	0.80862
1999	0.78723
2000	0.76446
2001	0.73831
2002	0.71269
2003	0.58347
2004	0.46207
2005	0.44551
2006	0.42872
2007	0.41226
2008	0.39624
2009	0.39282
2010	0.37793
2011	0.36457
2012	0.35194
2013	0.3397
2014	0.32779
2015	0.31639
2016	0.30544
2017	0.28606
2018	0.2781
2019	0.26154
2020	0.24658