Year	Number
1996	-0.907437264919281
1998	-0.881358742713928
2000	-0.710209369659424
2002	-0.574951589107513
2003	-0.481900811195374
2004	-0.441777735948563
2005	-0.341526746749878
2006	-0.500463128089905
2007	-0.52258163690567
2008	-0.62473601102829
2009	-0.964235186576843
2010	-1.10480070114136
2011	-1.21237993240356
2012	-1.32038903236389
2013	-1.13844060897827
2014	-1.30188941955566
2015	-1.25690579414368
2016	-1.2414299249649
2017	-1.27906346321106
2018	-1.34690141677856
2019	-1.38831329345703
2020	-1.35530030727386
2021	-1.18196296691895
2022	-1.06357324123383