Year	Percent
1991-01-01	4.79699993133545
1992-01-01	4.76399993896484
1993-01-01	4.77699995040894
1994-01-01	4.77699995040894
1995-01-01	4.77299976348877
1996-01-01	4.79199981689453
1997-01-01	4.78100013732910
1998-01-01	6.01200008392334
1999-01-01	7.27299976348877
2000-01-01	8.47299957275391
2001-01-01	9.79899978637695
2002-01-01	10.96899986267090
2003-01-01	12.27499961853030
2004-01-01	13.55700016021730
2005-01-01	14.69600009918210
2006-01-01	15.83899974823000
2007-01-01	17.88899993896480
2008-01-01	16.50799942016600
2009-01-01	15.12699985504150
2010-01-01	10.28299999237060
2011-01-01	10.43999958038330
2012-01-01	10.76900005340580
2013-01-01	11.09099960327150
2014-01-01	8.06200027465820
2015-01-01	18.19199943542480
2016-01-01	18.07799911499020
2017-01-01	17.95999908447270