Year	Percent
1986-01-01	2.25536737971513
1987-01-01	2.57696346584952
1988-01-01	4.00392498805412
1989-01-01	5.38296128511068
1990-01-01	6.45471662004180
1991-01-01	8.58017792032076
1992-01-01	8.86226910208424
1993-01-01	8.27237238083916
1994-01-01	7.00149649907938
1995-01-01	5.02595711122249
1996-01-01	4.81301785708352
1997-01-01	5.29740360671077
1998-01-01	6.06716930236268
1999-01-01	5.69486190670267
2000-01-01	4.62334676481714
2001-01-01	4.11782914387741
2002-01-01	3.78801572716030
2003-01-01	3.24177916672040
2004-01-01	2.47482260224796
2005-01-01	2.34695710544831
2006-01-01	2.33326112021700
2007-01-01	2.01940331007701
2008-01-01	2.48368532197593
2009-01-01	4.01696242667504
2010-01-01	4.03774271920065
2011-01-01	3.75944405791056
2012-01-01	4.19327175395579
2013-01-01	3.49858826943162
2014-01-01	3.11304804709560
2015-01-01	3.20484216351055
2016-01-01	3.14388571288061
2017-01-01	2.69445701633409