Year	Percent
1986-01-01	2.40272294661865
1987-01-01	2.70169608679764
1988-01-01	4.22974320303060
1989-01-01	5.57134786865381
1990-01-01	6.73610009036286
1991-01-01	9.03828966917478
1992-01-01	9.18452466005973
1993-01-01	8.61437349867162
1994-01-01	7.29639179310994
1995-01-01	5.28553787316609
1996-01-01	4.99326885657086
1997-01-01	5.48143459875155
1998-01-01	6.33889776263320
1999-01-01	5.80631358371175
2000-01-01	4.55961026537116
2001-01-01	4.21833604914463
2002-01-01	3.95781084132223
2003-01-01	3.26868993168858
2004-01-01	2.55112910068284
2005-01-01	2.49631248930288
2006-01-01	2.46478296843116
2007-01-01	2.20398392109612
2008-01-01	2.61370752421597
2009-01-01	4.24719639930086
2010-01-01	4.28432131191092
2011-01-01	4.12144353406606
2012-01-01	4.48744698917844
2013-01-01	3.61216850941700
2014-01-01	3.26923786503857
2015-01-01	3.35910489234412
2016-01-01	3.35478634495485
2017-01-01	2.86816701172170