Year	Number
1996	1.98697578907013
1998	2.05191779136658
2000	2.04835367202759
2002	2.05901455879211
2003	2.01248097419739
2004	1.98526263237
2005	2.01012587547302
2006	2.08340835571289
2007	2.14034938812256
2008	2.10857200622559
2009	2.06019997596741
2010	2.06414246559143
2011	2.0290699005127
2012	2.13839817047119
2013	2.12483501434326
2014	2.147784948349
2015	2.09469723701477
2016	1.94263672828674
2017	1.94451439380646
2018	1.96951818466187
2019	1.94505643844604
2020	2.04560995101929
2021	1.95900893211365
2022	2.0093138217926