Year	Percent
1999-01-01	6.190
2000-01-01	6.440
2001-01-01	8.360
2002-01-01	7.285
2003-01-01	9.090
2004-01-01	10.545
2005-01-01	13.475
2006-01-01	17.295
2007-01-01	18.930
2008-01-01	12.860
2009-01-01	17.350
2010-01-01	18.475
2011-01-01	14.660
2012-01-01	17.435
2013-01-01	17.820
2014-01-01	19.260
2015-01-01	25.620