Year	Percent
1999-01-01	39.1853209620301
2000-01-01	38.9813534772312
2001-01-01	39.1591962832978
2002-01-01	39.4195024034395
2003-01-01	39.0825699093970
2004-01-01	39.0225809114896
2005-01-01	39.2699076516781
2006-01-01	39.7177672580565
2007-01-01	40.1114577609893
2008-01-01	40.2533609065421
2009-01-01	39.5022868177553
2010-01-01	38.9652124035682
2011-01-01	39.2090858283335
2012-01-01	39.4576652018535
2013-01-01	40.0297094109570