Year	Percent
1986-01-01	33.1020922786793
1987-01-01	35.7481381178064
1988-01-01	39.8820296543541
1989-01-01	43.4970033744067
1990-01-01	43.3856113128067
1991-01-01	43.6127281643324
1992-01-01	43.6092210772440
1993-01-01	40.5803630263557
1994-01-01	37.5085057375218
1995-01-01	34.9641201183329
1996-01-01	31.3564873142489
1997-01-01	30.9024117774635
1998-01-01	29.7073988313959
1999-01-01	28.7471666382486
2000-01-01	28.1352006922018
2001-01-01	26.2164895045170
2002-01-01	22.9624763257742
2003-01-01	24.0144573816243
2004-01-01	21.9968769069540
2005-01-01	20.4559823540104
2006-01-01	18.9253762755545
2007-01-01	18.1276043610375
2008-01-01	18.3186933924288
2009-01-01	17.4507231111177
2010-01-01	17.4971037994523
2011-01-01	17.4291944091251
2012-01-01	17.1647752743724
2013-01-01	17.7230357478944
2014-01-01	16.6733476762203
2015-01-01	16.7849093931213
2016-01-01	15.6942115546746
2017-01-01	13.1398977483456