Year	Number
1996	-0.75019758939743
1998	-0.706548154354095
2000	-0.86523449420929
2002	-1.15901207923889
2003	-1.33635425567627
2004	-1.25664877891541
2005	-1.25851392745972
2006	-1.40944445133209
2007	-1.57048094272614
2008	-1.63578140735626
2009	-1.62595248222351
2010	-1.66915047168732
2011	-1.68640148639679
2012	-1.71477735042572
2013	-1.78581345081329
2014	-1.90905845165253
2015	-2.05221772193909
2016	-2.26685833930969
2017	-2.25875568389893
2018	-2.26574206352234
2019	-2.25972700119019
2020	-2.33331513404846
2021	-2.29995846748352
2022	-2.19721436500549