Year	Index
1979-01-01	34.6
1986-01-01	37.5
1991-01-01	38.2
1994-01-01	40.2
1997-01-01	40.8
2000-01-01	40.4
2004-01-01	40.5
2007-01-01	41.1
2010-01-01	40.4
2013-01-01	41
2016-01-01	41.5