Year	Percent
1991-01-01	22.6340007781982
1992-01-01	26.9650001525879
1993-01-01	23.0300006866455
1994-01-01	25.1089992523193
1995-01-01	20.7970008850098
1996-01-01	23.7350006103516
1997-01-01	22.2269992828369
1998-01-01	15.2889995574951
1999-01-01	14.9060001373291
2000-01-01	14.7810001373291
2001-01-01	15.1680002212524
2002-01-01	19.2539997100830
2003-01-01	24.0419998168945
2004-01-01	22.0779991149902
2005-01-01	20.1539993286133
2006-01-01	15.6870002746582
2007-01-01	18.9820003509521
2008-01-01	17.0259990692139
2009-01-01	25.9389991760254
2010-01-01	26.3260002136230
2011-01-01	27.3190002441406
2012-01-01	30.8869991302490
2013-01-01	32.6389999389648
2014-01-01	27.8780002593994
2015-01-01	24.3040008544922
2016-01-01	25.6389999389648
2017-01-01	25.6730003356934