Year	Number
1996	-1.64785850048065
1998	-1.79392170906067
2000	-1.60896074771881
2002	-1.95671439170837
2003	-2.37602686882019
2004	-2.27122640609741
2005	-2.05794286727905
2006	-1.90479671955109
2007	-1.80652725696564
2008	-1.85346233844757
2009	-1.83234584331512
2010	-1.53718483448029
2011	-1.28465557098389
2012	-1.40181040763855
2013	-1.29197180271149
2014	-1.11459410190582
2015	-1.0726637840271
2016	-0.887163996696472
2017	-0.779457688331604
2018	-0.806959629058838
2019	-0.979467272758484
2020	-0.701150596141815
2021	-0.954557538032532
2022	-0.641925930976868