Year	Number
1996	-0.765806436538696
1998	-0.842344582080841
2000	-1.39108908176422
2002	-1.79883396625519
2003	-1.85519170761108
2004	-1.97493207454681
2005	-2.20154404640198
2006	-1.93442177772522
2007	-2.07525968551636
2008	-2.06489610671997
2009	-2.08098173141479
2010	-2.00182390213013
2011	-1.8921492099762
2012	-1.87189054489136
2013	-1.85489869117737
2014	-1.892657995224
2015	-1.65623307228088
2016	-1.69492197036743
2017	-1.58345353603363
2018	-1.52565240859985
2019	-1.48651528358459
2020	-1.43441534042358
2021	-1.38610911369324
2022	-1.42596733570099