Year	Percent
1998-01-01	4.76774633716090
1999-01-01	4.59145495678780
2000-01-01	4.26420054578533
2001-01-01	3.83582658292115
2002-01-01	3.64591857671189
2003-01-01	3.57105829130107
2004-01-01	3.32329191965123
2005-01-01	3.20141268698783
2006-01-01	2.81895711399363
2007-01-01	2.52339807214716
2008-01-01	2.84375026933349
2009-01-01	3.44382595171610
2010-01-01	3.81659720464709
2011-01-01	3.80243010767936
2012-01-01	4.99622435016392
2013-01-01	5.77056924897590