Year	Percent
1998-01-01	11.92804880516660
1999-01-01	10.70334340761930
2000-01-01	10.57638067335620
2001-01-01	9.66529793777288
2002-01-01	9.04674732356777
2003-01-01	8.86555846157864
2004-01-01	8.90860943403813
2005-01-01	8.60618494603132
2006-01-01	8.07461031356777
2007-01-01	7.18767201472958
2008-01-01	6.68528847117498
2009-01-01	7.56292492037294
2010-01-01	7.63040940991404
2011-01-01	7.09953419229465
2012-01-01	7.04865183372523
2013-01-01	7.51255870680631
2014-01-01	7.94869353785993
2015-01-01	8.83218230823794
2016-01-01	8.57286995029919
2017-01-01	8.38082687422782