Year	Percent
1985-01-01	350.31
1986-01-01	346.02
1987-01-01	346.95
1988-01-01	357.84
1989-01-01	398.75
1990-01-01	426.05
1991-01-01	396.39
1992-01-01	357.78
1993-01-01	346.65
1994-01-01	340.34
1995-01-01	333.39
1996-01-01	337.20
1997-01-01	330.06
1998-01-01	330.98
1999-01-01	321.78
2000-01-01	298.21
2001-01-01	282.20
2002-01-01	270.83
2003-01-01	267.48
2004-01-01	262.69
2005-01-01	254.70
2006-01-01	246.78
2007-01-01	237.93
2008-01-01	240.60
2009-01-01	240.89
2010-01-01	235.75
2011-01-01	243.13
2012-01-01	262.47
2013-01-01	279.76
2014-01-01	299.79
2015-01-01	312.32