Year	Percent
1991-01-01	42.2919998168945
1992-01-01	42.6529998779297
1993-01-01	43.4510002136230
1994-01-01	41.1749992370605
1995-01-01	32.6629981994629
1996-01-01	28.3929996490479
1997-01-01	28.4689998626709
1998-01-01	25.5230007171631
1999-01-01	29.7099990844727
2000-01-01	33.2500000000000
2001-01-01	38.9529991149902
2002-01-01	35.5019989013672
2003-01-01	26.9549999237061
2004-01-01	24.3719997406006
2005-01-01	22.2299995422363
2006-01-01	19.4139995574951
2007-01-01	15.0600004196167
2008-01-01	12.6630001068115
2009-01-01	16.0909996032715
2010-01-01	21.9260005950928
2011-01-01	25.0540008544922
2012-01-01	28.1210002899170
2013-01-01	28.3969993591309
2014-01-01	23.7800006866455
2015-01-01	21.6299991607666
2016-01-01	17.2000007629395
2017-01-01	12.9659996032715