Year	Percent
1998-01-01	41.0646429902872
1999-01-01	42.0002711646657
2000-01-01	42.8508176149015
2001-01-01	43.4349490487050
2002-01-01	43.2001928093454
2003-01-01	43.0090010457451
2004-01-01	42.8083968402125
2005-01-01	42.9842928607685
2006-01-01	43.1101995533051
2007-01-01	43.2339640823564
2008-01-01	43.5550632688901
2009-01-01	42.8379930332362
2010-01-01	42.2474523386481
2011-01-01	40.8533845801493
2012-01-01	39.8174859899964
2013-01-01	39.0817438297533
2014-01-01	39.9111035142899