Year	Percent
1991-01-01	45.6910018920898
1992-01-01	46.0800018310547
1993-01-01	45.4990005493164
1994-01-01	45.2830009460449
1995-01-01	45.6940002441406
1996-01-01	45.5519981384277
1997-01-01	45.8950004577637
1998-01-01	45.9630012512207
1999-01-01	47.3610000610352
2000-01-01	48.7599983215332
2001-01-01	47.5870018005371
2002-01-01	47.4220008850098
2003-01-01	47.1329994201660
2004-01-01	47.9510002136230
2005-01-01	48.6839981079102
2006-01-01	48.6310005187988
2007-01-01	49.5769996643066
2008-01-01	49.8590011596680
2009-01-01	49.1599998474121
2010-01-01	49.4949989318848
2011-01-01	49.2830009460449
2012-01-01	49.1319999694824
2013-01-01	48.9830017089844
2014-01-01	48.9869995117188
2015-01-01	48.9129981994629
2016-01-01	49.0639991760254
2017-01-01	49.3849983215332