Year	Number
1996	-1.21172964572906
1998	-1.14174938201904
2000	-1.12044250965118
2002	-1.73340618610382
2003	-1.53887343406677
2004	-1.42424488067627
2005	-1.42799496650696
2006	-1.85155153274536
2007	-1.85726404190063
2008	-1.84381413459778
2009	-1.90398991107941
2010	-2.0206253528595
2011	-1.78938913345337
2012	-1.85292291641235
2013	-2.15489673614502
2014	-2.69919323921204
2015	-1.89358747005463
2016	-1.77954876422882
2017	-1.99353218078613
2018	-2.1720871925354
2019	-2.13577795028687
2020	-2.23620891571045
2021	-2.1267397403717
2022	-2.16247296333313