Year	Percent
1986-01-01	1.73832697530186
1987-01-01	1.43429982619230
1988-01-01	2.71976708778160
1989-01-01	3.20251245701944
1990-01-01	3.99588024329805
1991-01-01	4.37977358843109
1992-01-01	4.94706374665725
1993-01-01	3.81725222840724
1994-01-01	3.60531212303414
1995-01-01	2.80940845985690
1996-01-01	2.72042539797887
1997-01-01	2.99825624050173
1998-01-01	4.19559322244391
1999-01-01	4.24762700329538
2000-01-01	3.58338484798989
2001-01-01	2.88248745584237
2002-01-01	3.32104443504639
2003-01-01	3.82971334667258
2004-01-01	2.63060011940400
2005-01-01	1.92907867290508
2006-01-01	2.20435648003186
2007-01-01	1.40041737547128
2008-01-01	1.68952032296701
2009-01-01	2.37175157166955
2010-01-01	2.80086089751748
2011-01-01	3.06353525859927
2012-01-01	3.56932121549266
2013-01-01	3.62263382369720
2014-01-01	2.82456601607266
2015-01-01	3.39924249835490
2016-01-01	3.13129529494354
2017-01-01	2.78871610459815