Year	Number
1996	-1.40964531898499
1998	-1.29010999202728
2000	-0.966977536678314
2002	-1.06036186218262
2003	-1.18989634513855
2004	-1.34709358215332
2005	-1.36588943004608
2006	-1.13137221336365
2007	-1.10492873191833
2008	-1.0642728805542
2009	-1.05143511295319
2010	-1.07034814357758
2011	-1.07567989826202
2012	-1.29210209846497
2013	-1.45680749416351
2014	-1.64418196678162
2015	-1.65404057502747
2016	-1.70697629451752
2017	-1.80746412277222
2018	-1.52192282676697
2019	-1.5601292848587
2020	-1.46526992321014
2021	-1.44795417785645
2022	-1.48615753650665