Year	Percent
1999-01-01	38.0231822605673
2000-01-01	38.5829547661661
2001-01-01	38.5361681710085
2002-01-01	38.6589963920630
2003-01-01	39.2992374891068
2004-01-01	39.2225019776048
2005-01-01	39.2841287031929
2006-01-01	39.6135411052230
2007-01-01	39.6303857721599
2008-01-01	39.2152176872257
2009-01-01	38.3293279445081
2010-01-01	38.3813488594656
2011-01-01	38.7695329330123
2012-01-01	39.5607724393275
2013-01-01	40.2769111180501