Year	Number
1996	-1.7195029258728
1998	-1.73102784156799
2000	-1.79194414615631
2002	-1.53170728683472
2003	-1.41765511035919
2004	-1.41659450531006
2005	-1.41505181789398
2006	-1.21079874038696
2007	-1.16072571277618
2008	-1.21804714202881
2009	-1.19092416763306
2010	-1.2520444393158
2011	-1.22095167636871
2012	-1.15850818157196
2013	-1.36375725269318
2014	-1.33664906024933
2015	-1.37209689617157
2016	-1.31543433666229
2017	-1.36527264118195
2018	-1.32299840450287
2019	-1.39507031440735
2020	-1.46001219749451
2021	-1.41038012504578
2022	-1.43825364112854