Year	Number
1996	-1.81737661361694
1998	-1.53380000591278
2000	-1.73264276981354
2002	-1.60128676891327
2003	-2.39324522018433
2004	-3.18035173416138
2005	-2.68864846229553
2006	-2.82640218734741
2007	-2.77105069160461
2008	-2.46689653396606
2009	-2.17470788955688
2010	-2.23926711082459
2011	-1.84698355197906
2012	-1.93405020236969
2013	-2.01139044761658
2014	-2.48033785820007
2015	-2.25077962875366
2016	-2.30333304405212
2017	-2.29594826698303
2018	-2.52095818519592
2019	-2.6091480255127
2020	-2.47469043731689
2021	-2.38455939292908
2022	-2.47392463684082