Year	Percent
1991-01-01	45.7439994812012
1992-01-01	45.7490005493164
1993-01-01	45.8240013122559
1994-01-01	45.6349983215332
1995-01-01	45.2700004577637
1996-01-01	44.9010009765625
1997-01-01	44.1119995117188
1998-01-01	44.5600013732910
1999-01-01	45.0069999694824
2000-01-01	44.9640007019043
2001-01-01	45.1580009460449
2002-01-01	45.2929992675781
2003-01-01	45.3819999694824
2004-01-01	44.9290008544922
2005-01-01	45.0079994201660
2006-01-01	45.1030006408691
2007-01-01	45.1599998474121
2008-01-01	45.2000007629395
2009-01-01	45.2509994506836
2010-01-01	45.9220008850098
2011-01-01	47.0330009460449
2012-01-01	49.8009986877441
2013-01-01	48.8590011596680
2014-01-01	49.6020011901855
2015-01-01	49.0559997558594
2016-01-01	46.9550018310547
2017-01-01	47.2980003356934