Year	Percent
1991-01-01	55.2070007324219
1992-01-01	55.1570014953613
1993-01-01	55.1360015869141
1994-01-01	55.1720008850098
1995-01-01	55.2599983215332
1996-01-01	55.4039993286133
1997-01-01	55.4319992065430
1998-01-01	55.4770011901855
1999-01-01	55.5359992980957
2000-01-01	55.5960006713867
2001-01-01	55.5760002136230
2002-01-01	55.5369987487793
2003-01-01	55.1259994506836
2004-01-01	55.1080017089844
2005-01-01	55.1640014648438
2006-01-01	55.4189987182617
2007-01-01	55.1129989624023
2008-01-01	54.8019981384277
2009-01-01	54.2490005493164
2010-01-01	55.0610008239746
2011-01-01	54.8079986572266
2012-01-01	54.5670013427734
2013-01-01	54.1899986267090
2014-01-01	54.1090011596680
2015-01-01	54.0270004272461
2016-01-01	53.9799995422363
2017-01-01	54.0320014953613