Year	Percent
1999-01-01	7.19011867270191
2000-01-01	6.46230327341148
2001-01-01	5.65059505118530
2002-01-01	5.89492952994134
2003-01-01	6.32923639622598
2004-01-01	5.85496021888378
2005-01-01	6.05489668798684
2006-01-01	4.89211249953671
2007-01-01	3.97009431492575
2008-01-01	3.99482069299745
2009-01-01	5.89877155465037
2010-01-01	7.41474046227989
2011-01-01	8.16177811074011
2012-01-01	8.38719141773958
2013-01-01	9.42211158748473
2014-01-01	8.92218711510538
2015-01-01	8.05599624622573
2016-01-01	7.49103523604462
2017-01-01	5.77964702255179