Year	Percent
1998-01-01	40.410
1999-01-01	39.615
2000-01-01	42.400
2001-01-01	42.500
2002-01-01	41.000
2003-01-01	42.960
2004-01-01	36.025
2005-01-01	32.335
2006-01-01	27.940
2007-01-01	29.055
2008-01-01	33.225
2009-01-01	29.455
2010-01-01	22.310
2011-01-01	19.070
2012-01-01	21.930
2013-01-01	22.985
2014-01-01	28.850
2015-01-01	17.035