Year	Percent
1998-01-01	53.6801466262558
1999-01-01	53.2537871724321
2000-01-01	47.7394386599461
2001-01-01	45.8160092147096
2002-01-01	45.8022478007928
2003-01-01	45.5451218965159
2004-01-01	45.4291413718678
2005-01-01	45.9533125131877
2006-01-01	46.6109670605569
2007-01-01	47.3139576968562
2008-01-01	47.8508832564602
2009-01-01	46.2145374611904
2010-01-01	45.8045560999309
2011-01-01	46.1054146700901
2012-01-01	46.0549254705267
2013-01-01	45.3475011215533