Year	Percent
1995-01-01	27.5387413891579
1996-01-01	27.8335360082882
1997-01-01	27.7740699603583
1998-01-01	27.8791511664117
1999-01-01	27.6158475005663
2000-01-01	27.6554127826289
2001-01-01	27.7361700835639
2002-01-01	26.9914269654546
2003-01-01	26.5872357285495
2004-01-01	26.8350607193733
2005-01-01	27.1984242937561
2006-01-01	27.6819993902468
2007-01-01	27.4665191090174
2008-01-01	27.2683474365893
2009-01-01	28.0901693408973
2010-01-01	28.4376214055334
2011-01-01	28.5968545346906
2012-01-01	28.9812473301130
2013-01-01	29.1274461019721
2014-01-01	29.4363364908266
2015-01-01	29.4055954934166
2016-01-01	29.7353983096335
2017-01-01	29.8369091991645