Year	Percent
1991-01-01	45.6049995422363
1992-01-01	45.9189987182617
1993-01-01	46.1669998168945
1994-01-01	46.7099990844727
1995-01-01	47.0519981384277
1996-01-01	47.6780014038086
1997-01-01	48.0470008850098
1998-01-01	48.4879989624023
1999-01-01	48.5429992675781
2000-01-01	49.0509986877441
2001-01-01	49.7789993286133
2002-01-01	50.1870002746582
2003-01-01	50.7519989013672
2004-01-01	51.0870018005371
2005-01-01	51.7739982604980
2006-01-01	52.4970016479492
2007-01-01	53.2879981994629
2008-01-01	53.9269981384277
2009-01-01	54.9500007629395
2010-01-01	54.0789985656738
2011-01-01	53.6129989624023
2012-01-01	53.3349990844727
2013-01-01	53.2690010070801
2014-01-01	53.3849983215332
2015-01-01	53.3759994506836
2016-01-01	53.0690002441406
2017-01-01	52.9609985351563