Year	Percent
1991-01-01	59.9490013122559
1992-01-01	59.8880004882813
1993-01-01	60.2109985351563
1994-01-01	60.0979995727539
1995-01-01	59.8709983825684
1996-01-01	60.1139984130859
1997-01-01	60.0810012817383
1998-01-01	59.9169998168945
1999-01-01	59.7159996032715
2000-01-01	59.8610000610352
2001-01-01	59.4589996337891
2002-01-01	59.3359985351563
2003-01-01	59.1100006103516
2004-01-01	59.0270004272461
2005-01-01	58.9809989929199
2006-01-01	58.9210014343262
2007-01-01	58.7610015869141
2008-01-01	58.1389999389648
2009-01-01	58.1710014343262
2010-01-01	58.3489990234375
2011-01-01	59.4869995117188
2012-01-01	60.4570007324219
2013-01-01	61.7999992370605
2014-01-01	62.2290000915527
2015-01-01	62.3250007629395
2016-01-01	62.1100006103516
2017-01-01	62.3100013732910