Year	Percent of Total
1990-01-01	49.3089810332132
1991-01-01	49.2801539810783
1992-01-01	49.2637249479118
1993-01-01	49.2565252474380
1994-01-01	49.2610786228978
1995-01-01	49.2831498772588
1996-01-01	49.2483525910990
1997-01-01	49.3087605754773
1998-01-01	49.4367740916082
1999-01-01	49.6256263072782
2000-01-01	49.9007914653667
2001-01-01	50.2262788061957
2002-01-01	50.5653809696160
2003-01-01	50.9561006033773
2004-01-01	51.4194611307345
2005-01-01	51.9371003056342
2006-01-01	52.5279946263872
2007-01-01	53.1329210584813
2008-01-01	53.7366930491056
2009-01-01	54.3213161043602
2010-01-01	54.8723587837109
2011-01-01	55.3151745386019
2012-01-01	55.7668988768231
2013-01-01	56.1978950058034
2014-01-01	56.5768029223623
2015-01-01	56.8944884753728
2016-01-01	57.1608562831567
2017-01-01	57.3834460132289