Year	Percent
1991-01-01	53.9199981689453
1992-01-01	53.2820014953613
1993-01-01	52.3590011596680
1994-01-01	51.1370010375977
1995-01-01	50.7439994812012
1996-01-01	50.7360000610352
1997-01-01	50.6539993286133
1998-01-01	50.8170013427734
1999-01-01	48.8380012512207
2000-01-01	47.0960006713867
2001-01-01	46.2140007019043
2002-01-01	44.5169982910156
2003-01-01	44.3240013122559
2004-01-01	44.1430015563965
2005-01-01	45.3030014038086
2006-01-01	46.6969985961914
2007-01-01	48.8400001525879
2008-01-01	50.7070007324219
2009-01-01	50.7400016784668
2010-01-01	50.5279998779297
2011-01-01	50.6739997863770
2012-01-01	50.7050018310547
2013-01-01	50.6370010375977
2014-01-01	51.7319984436035
2015-01-01	52.4300003051758
2016-01-01	53.3580017089844
2017-01-01	53.8149986267090