Year	Number
1996	-1.95985543727875
1998	-1.91686367988586
2000	-1.97572016716003
2002	-1.53170728683472
2003	-1.90459001064301
2004	-1.8433358669281
2005	-2.1309552192688
2006	-2.07395672798157
2007	-2.19994497299194
2008	-2.29601812362671
2009	-2.15730476379395
2010	-2.1699275970459
2011	-2.15188980102539
2012	-2.19294190406799
2013	-2.1953136920929
2014	-2.43926000595093
2015	-2.21718955039978
2016	-2.20610427856445
2017	-2.25891923904419
2018	-2.21182322502136
2019	-2.2808883190155
2020	-2.13139939308167
2021	-2.08389329910278
2022	-2.02636790275574