Year	Percent
1991-01-01	20.6630001068115
1992-01-01	18.0939998626709
1993-01-01	17.9370002746582
1994-01-01	20.8540000915527
1995-01-01	20.6019992828369
1996-01-01	26.4629993438721
1997-01-01	28.8509998321533
1998-01-01	28.4459991455078
1999-01-01	29.8729991912842
2000-01-01	28.4099998474121
2001-01-01	26.4580001831055
2002-01-01	24.4370002746582
2003-01-01	22.7430000305176
2004-01-01	19.8010005950928
2005-01-01	18.2099990844727
2006-01-01	16.6590003967285
2007-01-01	13.9259996414185
2008-01-01	14.3819999694824
2009-01-01	13.8629999160767
2010-01-01	14.7379999160767
2011-01-01	14.6059999465942
2012-01-01	14.0629997253418
2013-01-01	13.5480003356934
2014-01-01	13.4200000762939
2015-01-01	13.3120002746582
2016-01-01	13.4910001754761
2017-01-01	13.7919998168945