Year	Number
1996	-2.28123259544373
1998	-2.12903618812561
2000	-2.14746236801147
2002	-1.88340437412262
2003	-2.06944012641907
2004	-2.27137184143066
2005	-2.2811017036438
2006	-2.28328084945679
2007	-2.27965545654297
2008	-2.18588447570801
2009	-2.39381313323975
2010	-2.44549250602722
2011	-2.45393967628479
2012	-2.5266900062561
2013	-2.522705078125
2014	-2.1869695186615
2015	-2.35838413238525
2016	-2.350102186203
2017	-2.36729145050049
2018	-2.38481521606445
2019	-2.41876745223999
2020	-2.37046599388123
2021	-2.34278678894043
2022	-2.39301609992981