Year	Index
1987-01-01	21
1989-01-01	25
1993-01-01	27.9
2004-01-01	29.9
2005-01-01	34.7
2006-01-01	28.3
2007-01-01	27.9
2008-01-01	27.5
2009-01-01	27
2010-01-01	29.4
2011-01-01	29.2
2012-01-01	30.8
2013-01-01	31.5
2014-01-01	30.9
2015-01-01	30.4