Year	Number
1996	-1.64583265781403
1998	-1.50525808334351
2000	-1.38280534744263
2002	-1.1117959022522
2003	-1.14990878105164
2004	-1.22227311134338
2005	-1.26609790325165
2006	-1.35194134712219
2007	-1.29212081432343
2008	-1.35568141937256
2009	-1.33212602138519
2010	-1.43107783794403
2011	-1.38084805011749
2012	-1.42240357398987
2013	-1.50412678718567
2014	-1.49548387527466
2015	-1.56908190250397
2016	-1.68945837020874
2017	-1.72128844261169
2018	-1.69865822792053
2019	-1.79593408107758
2020	-1.77847802639008
2021	-1.70155775547028
2022	-1.67276620864868