Year	Number
1996	-0.987331032752991
1998	-1.05510711669922
2000	-0.943567037582397
2002	-1.07800042629242
2003	-1.22070097923279
2004	-1.15692710876465
2005	-1.40693187713623
2006	-1.1641184091568
2007	-1.13222634792328
2008	-1.28207445144653
2009	-1.27956962585449
2010	-1.37868785858154
2011	-1.41596949100494
2012	-1.43261659145355
2013	-1.48639118671417
2014	-1.55744516849518
2015	-1.51032912731171
2016	-1.55881643295288
2017	-1.47614145278931
2018	-1.62895309925079
2019	-1.65864384174347
2020	-1.54020392894745
2021	-1.66320180892944
2022	-1.70530915260315