Year	Index
1997-01-01	36.9
1998-01-01	39.5
1999-01-01	42.6
2000-01-01	36.4
2001-01-01	38
2002-01-01	35.8
2003-01-01	34.9
2004-01-01	35
2005-01-01	36.3
2006-01-01	35.4
2007-01-01	34.4
2008-01-01	34.7
2009-01-01	32.9
2010-01-01	32.1
2011-01-01	30.6
2012-01-01	29.2
2013-01-01	28.5
2014-01-01	26.8
2015-01-01	27
2016-01-01	26.3