Year	Number
1996	-2.14465737342834
1998	-2.13615322113037
2000	-2.19043397903442
2002	-1.93713533878326
2003	-2.04828476905823
2004	-2.28866386413574
2005	-2.21945238113403
2006	-2.35046291351318
2007	-2.41922998428345
2008	-2.59087705612183
2009	-2.45029664039612
2010	-2.40626358985901
2011	-2.3382785320282
2012	-2.41820406913757
2013	-2.40616345405579
2014	-2.35551500320435
2015	-2.31554555892944
2016	-2.31646156311035
2017	-2.26308059692383
2018	-2.29871559143066
2019	-2.38080906867981
2020	-2.31353354454041
2021	-2.28185629844666
2022	-2.28685545921326