Year	Number
1996	-0.68858790397644
1998	-0.987684667110443
2000	-1.05684018135071
2002	-1.19894194602966
2003	-1.29204165935516
2004	-1.38801848888397
2005	-1.45624136924744
2006	-1.49391078948975
2007	-1.52461135387421
2008	-1.4815468788147
2009	-1.3565925359726
2010	-1.38399815559387
2011	-1.37212538719177
2012	-1.29685842990875
2013	-1.28896832466125
2014	-1.26604235172272
2015	-1.2256110906601
2016	-1.11821472644806
2017	-1.16602909564972
2018	-1.09365093708038
2019	-0.972789764404297
2020	-0.730569243431091
2021	-0.686524271965027
2022	-0.64258873462677