Year	Percent
1998-01-01	6.28993472702419
1999-01-01	5.20820686695212
2000-01-01	5.00739309091063
2001-01-01	5.03073961375341
2002-01-01	6.02636897034106
2003-01-01	7.22095933940978
2004-01-01	7.56986879738900
2005-01-01	8.63161397031841
2006-01-01	8.90321630101542
2007-01-01	9.49088440919423
2008-01-01	8.75024008774544
2009-01-01	10.09169159196490
2010-01-01	11.86536473079680
2011-01-01	13.04627209889670
2012-01-01	15.50145563658380
2013-01-01	16.36872867969760
2014-01-01	14.32694302140160
2015-01-01	12.74680112106650
2016-01-01	11.16720486916120
2017-01-01	9.35057880080369