Year	Index
1991-01-01	29.2
1994-01-01	29.2
2000-01-01	28.8
2001-01-01	30.3
2004-01-01	30.4
2006-01-01	31.3
2007-01-01	31.3
2010-01-01	30.2
2011-01-01	30.5
2013-01-01	31.1
2015-01-01	31.7