Year	Percent
1999-01-01	39.7091691344918
2000-01-01	39.0839941135245
2001-01-01	39.4348976941019
2002-01-01	39.4348123293001
2003-01-01	40.1114213427334
2004-01-01	40.3718115684076
2005-01-01	41.1797070892720
2006-01-01	42.7201625473169
2007-01-01	43.7301113207881
2008-01-01	45.1042634793158
2009-01-01	43.7445482079770
2010-01-01	42.7441755915130
2011-01-01	42.9364200038124
2012-01-01	43.0948503969062
2013-01-01	43.0481629333925