Year	Number
1996	-0.951336085796356
1998	-0.857599556446075
2000	-0.932390332221985
2002	-1.07524108886719
2003	-1.25318002700806
2004	-1.23303318023682
2005	-1.28215098381042
2006	-1.50055873394012
2007	-1.55446839332581
2008	-1.56973898410797
2009	-1.58175098896027
2010	-1.60616195201874
2011	-1.5831161737442
2012	-1.60021269321442
2013	-1.60837185382843
2014	-1.58074295520782
2015	-1.5135885477066
2016	-1.34296941757202
2017	-1.2998480796814
2018	-1.33044922351837
2019	-1.38640606403351
2020	-1.4760000705719
2021	-1.46777892112732
2022	-1.45943284034729