Year	Number
1996	-1.36392831802368
1998	-1.23163819313049
2000	-1.47073936462402
2002	-1.82439136505127
2003	-1.93292152881622
2004	-1.90701413154602
2005	-2.18489861488342
2006	-2.0841166973114
2007	-2.11592626571655
2008	-2.15996932983398
2009	-2.20277786254883
2010	-2.19829225540161
2011	-2.22605419158936
2012	-2.20876717567444
2013	-2.19641661643982
2014	-2.1130199432373
2015	-2.1065878868103
2016	-2.17027592658997
2017	-2.16618585586548
2018	-2.18433403968811
2019	-2.20522332191467
2020	-2.06482625007629
2021	-1.93016028404236
2022	-1.8799307346344