Year	Percent
1991-01-01	54.4939994812012
1992-01-01	54.2089996337891
1993-01-01	54.0639991760254
1994-01-01	54.5139999389648
1995-01-01	55.1720008850098
1996-01-01	55.1430015563965
1997-01-01	54.8240013122559
1998-01-01	54.6920013427734
1999-01-01	54.5660018920898
2000-01-01	54.6170005798340
2001-01-01	54.6790008544922
2002-01-01	55.1679992675781
2003-01-01	54.7420005798340
2004-01-01	55.0419998168945
2005-01-01	49.8790016174316
2006-01-01	44.5270004272461
2007-01-01	39.1640014648438
2008-01-01	33.7260017395020
2009-01-01	28.0699996948242
2010-01-01	22.7830009460449
2011-01-01	16.9260005950928
2012-01-01	16.9570007324219
2013-01-01	16.9979991912842
2014-01-01	16.9489994049072
2015-01-01	16.9050006866455
2016-01-01	18.0310001373291
2017-01-01	19.0900001525879