Year	Number
1996	-1.52469968795776
1998	-1.56102991104126
2000	-1.59922921657562
2002	-1.62372946739197
2003	-1.66345012187958
2004	-1.63894009590149
2005	-1.6835001707077
2006	-1.8262654542923
2007	-1.88797950744629
2008	-1.89406704902649
2009	-1.80686867237091
2010	-1.86019432544708
2011	-1.89961373806
2012	-1.90504097938538
2013	-1.96989130973816
2014	-1.97519636154175
2015	-1.99926972389221
2016	-1.94751513004303
2017	-1.97092747688293
2018	-1.87332701683044
2019	-1.87896883487701
2020	-1.80994868278503
2021	-1.713658452034
2022	-1.66811335086823