Year	Number
1996	-1.41612029075623
1998	-1.37878561019897
2000	-1.56851708889008
2002	-1.39800202846527
2003	-1.48403012752533
2004	-1.47995054721832
2005	-1.12846672534943
2006	-0.983238279819489
2007	-1.0786669254303
2008	-1.03810000419617
2009	-1.15993535518646
2010	-1.20540106296539
2011	-1.15380430221558
2012	-1.08392977714539
2013	-1.07643830776215
2014	-0.970426797866821
2015	-1.18596768379211
2016	-1.48484182357788
2017	-1.41499578952789
2018	-1.5139068365097
2019	-1.45360052585602
2020	-1.33961689472198
2021	-1.31259334087372
2022	-1.27713978290558