Year	Number
1996	-1.25611138343811
1998	-1.19058036804199
2000	-1.13099467754364
2002	-1.10900986194611
2003	-1.51830554008484
2004	-1.33303308486938
2005	-1.50373816490173
2006	-1.55299854278564
2007	-1.54328119754791
2008	-1.62577319145203
2009	-1.52672183513641
2010	-1.51355981826782
2011	-1.48459410667419
2012	-1.46390414237976
2013	-1.39775705337524
2014	-1.15042281150818
2015	-1.21049761772156
2016	-1.4068295955658
2017	-1.32141256332397
2018	-1.33120822906494
2019	-1.31415891647339
2020	-1.33145833015442
2021	-1.34138870239258
2022	-1.37252998352051