Year	Percent
1991-01-01	72.7180023193359
1992-01-01	72.4769973754883
1993-01-01	72.3580017089844
1994-01-01	72.1839981079102
1995-01-01	72.0270004272461
1996-01-01	71.8820037841797
1997-01-01	71.7610015869141
1998-01-01	71.6320037841797
1999-01-01	71.3280029296875
2000-01-01	70.9400024414063
2001-01-01	70.6009979248047
2002-01-01	70.2409973144531
2003-01-01	69.8150024414063
2004-01-01	69.3870010375977
2005-01-01	68.9420013427734
2006-01-01	68.4899978637695
2007-01-01	68.0599975585938
2008-01-01	67.6809997558594
2009-01-01	67.2580032348633
2010-01-01	66.8479995727539
2011-01-01	66.5800018310547
2012-01-01	66.2480010986328
2013-01-01	65.8730010986328
2014-01-01	65.5039978027344
2015-01-01	65.1429977416992
2016-01-01	64.8000030517578
2017-01-01	64.5599975585938