Year	Number
1996	1.88219606876373
1998	1.86216461658478
2000	1.76882231235504
2002	1.77972555160522
2003	1.74633467197418
2004	1.86802077293396
2005	1.76157212257385
2006	1.6667982339859
2007	1.64163875579834
2008	1.63480663299561
2009	1.50809645652771
2010	1.6179975271225
2011	1.60419464111328
2012	1.59121036529541
2013	1.51276922225952
2014	1.62398397922516
2015	1.70567572116852
2016	1.57455956935883
2017	1.43069469928741
2018	1.36168932914734
2019	1.44990789890289
2020	1.33266663551331
2021	1.24177372455597
2022	1.23863482475281