Year	Number
1996	1.74236369132996
1998	1.87730169296265
2000	1.84907865524292
2002	1.86085593700409
2003	1.92467999458313
2004	1.90069770812988
2005	1.88245940208435
2006	1.89211332798004
2007	1.75481534004211
2008	1.78248238563538
2009	1.74208331108093
2010	1.77782678604126
2011	1.77254545688629
2012	1.75697004795074
2013	1.78125011920929
2014	1.75435316562653
2015	1.73175251483917
2016	1.74549269676208
2017	1.81537175178528
2018	1.67517793178558
2019	1.69739508628845
2020	1.59874486923218
2021	1.56352460384369
2022	1.56707048416138