Year	Percent
1998-01-01	7.33267467362883
1999-01-01	5.51955745805110
2000-01-01	4.23583860128430
2001-01-01	3.77728010423570
2002-01-01	4.08136547094094
2003-01-01	4.34269485393992
2004-01-01	4.07385078149644
2005-01-01	4.00123305028613
2006-01-01	4.20728129696944
2007-01-01	4.92684760381202
2008-01-01	5.69494075629072
2009-01-01	9.50223874977359
2010-01-01	11.40728299116580
2011-01-01	12.49816948742190
2012-01-01	12.74962936377350
2013-01-01	12.42393255015460
2014-01-01	10.87417105155190
2015-01-01	8.90690951785281
2016-01-01	7.58148011291571
2017-01-01	6.29468190632886