Year	Percent
1991-01-01	38.9900016784668
1992-01-01	39.4039993286133
1993-01-01	39.5110015869141
1994-01-01	39.4640007019043
1995-01-01	40.0589981079102
1996-01-01	39.5970001220703
1997-01-01	39.8660011291504
1998-01-01	40.0489997863770
1999-01-01	40.2519989013672
2000-01-01	40.4129981994629
2001-01-01	40.8279991149902
2002-01-01	41.0379981994629
2003-01-01	40.8909988403320
2004-01-01	41.6250000000000
2005-01-01	41.8160018920898
2006-01-01	42.4020004272461
2007-01-01	42.7639999389648
2008-01-01	43.2179985046387
2009-01-01	43.6969985961914
2010-01-01	43.7830009460449
2011-01-01	44.2319984436035
2012-01-01	43.3160018920898
2013-01-01	43.0330009460449
2014-01-01	42.7739982604980
2015-01-01	42.7809982299805
2016-01-01	42.7949981689453
2017-01-01	43.1959991455078