Year	Percent
1988-01-01	27.3420
1989-01-01	23.5019
1990-01-01	23.5562
1991-01-01	28.7085
1992-01-01	29.8099
1993-01-01	36.3214
1994-01-01	35.3982
1995-01-01	33.3443
1996-01-01	32.8614
1997-01-01	25.5722
1998-01-01	25.9976
1999-01-01	22.7564
2000-01-01	18.5614
2001-01-01	17.2838
2002-01-01	17.4455
2003-01-01	16.9317
2004-01-01	14.5308
2005-01-01	12.4026
2006-01-01	12.4455
2007-01-01	12.1292
2008-01-01	11.0265
2009-01-01	24.2526
2010-01-01	28.2001
2011-01-01	31.0581
2012-01-01	35.4917
2013-01-01	33.7097
2014-01-01	38.7336
2015-01-01	43.6697
2016-01-01	44.9898