Year	Number
1996	-1.23917865753174
1998	-1.2574280500412
2000	-1.200798869133
2002	-1.44006717205048
2003	-1.24661719799042
2004	-1.33680975437164
2005	-1.47870898246765
2006	-1.45359468460083
2007	-1.22470498085022
2008	-1.17363584041595
2009	-1.32619547843933
2010	-1.41664183139801
2011	-1.45240187644958
2012	-1.29927587509155
2013	-1.23522520065308
2014	-1.13419890403748
2015	-1.13810276985168
2016	-1.12766790390015
2017	-1.13491332530975
2018	-1.09812998771667
2019	-1.08138024806976
2020	-1.11273300647736
2021	-0.922040820121765
2022	-0.854107201099396