Year	Index
1998-01-01	32
1999-01-01	31.7
2000-01-01	31.2
2001-01-01	30.6
2002-01-01	30.3
2003-01-01	28.8
2004-01-01	26.5
2005-01-01	27.6
2006-01-01	28.3
2007-01-01	29.6
2008-01-01	27.8
2009-01-01	27.7
2010-01-01	28.6
2011-01-01	27.2
2012-01-01	26.5
2013-01-01	26.6
2014-01-01	27.2
2015-01-01	26.7
2016-01-01	27