Year	Percent
1998-01-01	11.41813919869240
1999-01-01	10.21152665713320
2000-01-01	9.80018491572632
2001-01-01	9.12155946083026
2002-01-01	9.08117266088446
2003-01-01	9.01690825254287
2004-01-01	8.81603051666748
2005-01-01	8.37866977247699
2006-01-01	7.71488138761198
2007-01-01	6.85399293792235
2008-01-01	6.36275684497570
2009-01-01	8.23778151265358
2010-01-01	8.38698090704012
2011-01-01	7.77496849999230
2012-01-01	7.68181000107030
2013-01-01	8.18639218587688
2014-01-01	8.65780155047546
2015-01-01	9.36731076569650
2016-01-01	8.81128642257094
2017-01-01	8.63445013273565