Year	Percent
1991-01-01	57.9589996337891
1992-01-01	57.9309997558594
1993-01-01	55.6559982299805
1994-01-01	54.6250000000000
1995-01-01	54.2550010681152
1996-01-01	52.4280014038086
1997-01-01	51.2560005187988
1998-01-01	51.7550010681152
1999-01-01	50.4239997863770
2000-01-01	49.6980018615723
2001-01-01	49.0769996643066
2002-01-01	48.3569984436035
2003-01-01	47.7760009765625
2004-01-01	47.2770004272461
2005-01-01	46.9020004272461
2006-01-01	46.5950012207031
2007-01-01	46.4039993286133
2008-01-01	46.2179985046387
2009-01-01	46.4039993286133
2010-01-01	48.2480010986328
2011-01-01	49.4379997253418
2012-01-01	49.9239997863770
2013-01-01	50.9379997253418
2014-01-01	49.9160003662109
2015-01-01	48.8839988708496
2016-01-01	49.0950012207031
2017-01-01	49.1739997863770