Year	Number
1996	-1.40605127811432
1998	-1.35108137130737
2000	-1.41228187084198
2002	-1.38285386562347
2003	-1.19755887985229
2004	-1.32439291477203
2005	-1.58419597148895
2006	-1.47496902942657
2007	-1.52851343154907
2008	-1.37209057807922
2009	-1.39648199081421
2010	-1.39312899112701
2011	-1.31311178207397
2012	-1.45320987701416
2013	-1.62511491775513
2014	-1.87946033477783
2015	-1.81012177467346
2016	-1.8060200214386
2017	-1.79320251941681
2018	-1.735271692276
2019	-1.780198097229
2020	-1.72857892513275
2021	-1.67205941677094
2022	-1.7093962430954