Year	Percent
1991-01-01	31.0750007629395
1992-01-01	32.2159996032715
1993-01-01	40.6769981384277
1994-01-01	39.4700012207031
1995-01-01	36.2779998779297
1996-01-01	34.7480010986328
1997-01-01	29.7660007476807
1998-01-01	34.5559997558594
1999-01-01	37.5680007934570
2000-01-01	35.5649986267090
2001-01-01	36.0340003967285
2002-01-01	33.9539985656738
2003-01-01	33.1699981689453
2004-01-01	32.1150016784668
2005-01-01	31.0690002441406
2006-01-01	30.1369991302490
2007-01-01	26.9430007934570
2008-01-01	26.3460006713867
2009-01-01	27.5200004577637
2010-01-01	29.2390003204346
2011-01-01	28.7719993591309
2012-01-01	27.7040004730225
2013-01-01	30.4860000610352
2014-01-01	39.3590011596680
2015-01-01	40.1440010070801
2016-01-01	32.7319984436035
2017-01-01	30.0160007476807