Year	Percent
1986-01-01	12.2456214992334
1987-01-01	13.0529982289556
1988-01-01	15.2041695480983
1989-01-01	16.4104409789845
1990-01-01	16.7855989355638
1991-01-01	17.0065814636361
1992-01-01	17.5189831349927
1993-01-01	17.4088629301886
1994-01-01	16.8904747891269
1995-01-01	16.3447019247810
1996-01-01	16.0657216711315
1997-01-01	16.0327639671849
1998-01-01	16.6472461257443
1999-01-01	17.0120791205586
2000-01-01	16.8910188049586
2001-01-01	16.7378824648366
2002-01-01	16.1383284938077
2003-01-01	17.0466741082751
2004-01-01	16.3299144369032
2005-01-01	15.6393193633442
2006-01-01	15.0193244936256
2007-01-01	15.0950030375037
2008-01-01	15.6712987827735
2009-01-01	16.3221694867464
2010-01-01	16.7080555478282
2011-01-01	16.7308438952098
2012-01-01	17.2781523251414
2013-01-01	17.2585281841060
2014-01-01	16.1666347721763
2015-01-01	16.0724063606967
2016-01-01	15.0418636498570
2017-01-01	14.2592721291077