Year	Number
1996	-1.26436936855316
1998	-1.18792462348938
2000	-1.2123749256134
2002	-1.22288250923157
2003	-1.27593719959259
2004	-1.38037264347076
2005	-1.42684757709503
2006	-1.36262607574463
2007	-1.21237552165985
2008	-1.19891607761383
2009	-1.22026312351227
2010	-1.23483073711395
2011	-1.22866559028625
2012	-1.23995065689087
2013	-1.31558036804199
2014	-1.54029679298401
2015	-1.57206654548645
2016	-1.60282599925995
2017	-1.64540529251099
2018	-1.54276144504547
2019	-1.56337535381317
2020	-1.53900897502899
2021	-1.58688843250275
2022	-1.60171604156494