Year	Percent
1995-01-01	18.4929488429531
1996-01-01	18.7127197223229
1997-01-01	18.5291536158685
1998-01-01	18.6109244684764
1999-01-01	18.1557838374847
2000-01-01	18.0885410590578
2001-01-01	18.1015380246791
2002-01-01	17.3289037968958
2003-01-01	16.9547879497275
2004-01-01	17.1576040748859
2005-01-01	17.5397171933458
2006-01-01	17.9299054275714
2007-01-01	17.6401826343422
2008-01-01	17.4016735810722
2009-01-01	18.3146191640774
2010-01-01	18.6424338382644
2011-01-01	18.5982031494743
2012-01-01	18.7171039458584
2013-01-01	18.6031419434798
2014-01-01	18.7053670646697
2015-01-01	18.2252809595105
2016-01-01	18.2127095206095
2017-01-01	18.1005951285307