Year	Number
1996	-1.15406012535095
1998	-1.15319609642029
2000	-1.06633913516998
2002	-1.31521606445313
2003	-1.16723418235779
2004	-1.27538299560547
2005	-1.14158737659454
2006	-1.39341068267822
2007	-1.26028740406036
2008	-1.23535180091858
2009	-1.34402370452881
2010	-1.38278949260712
2011	-1.38583624362946
2012	-1.35402989387512
2013	-1.38206601142883
2014	-1.61946833133698
2015	-1.65658473968506
2016	-1.67480325698853
2017	-1.72375965118408
2018	-1.64309453964233
2019	-1.66125178337097
2020	-1.60865199565887
2021	-1.6346629858017
2022	-1.66108667850494