Year	Number
1996	-1.36058640480042
1998	-1.29849338531494
2000	-1.38543748855591
2002	-1.28121972084045
2003	-1.41801536083221
2004	-1.19761419296265
2005	-1.38486194610596
2006	-1.20465230941772
2007	-1.31586444377899
2008	-1.44146597385406
2009	-1.27479517459869
2010	-1.34485065937042
2011	-1.31654858589172
2012	-1.47798550128937
2013	-1.46377813816071
2014	-1.44510698318481
2015	-1.50451040267944
2016	-1.48627293109894
2017	-1.58541584014893
2018	-1.6440646648407
2019	-1.66968011856079
2020	-1.5709011554718
2021	-1.4769868850708
2022	-1.58131110668182