Year	Number
1996	1.78326535224915
1998	1.71170830726624
2000	1.71064364910126
2002	1.71136832237244
2003	1.7327196598053
2004	1.74865007400513
2005	1.64963126182556
2006	1.80342781543732
2007	1.92670845985413
2008	1.87364733219147
2009	1.87865126132965
2010	1.87385439872742
2011	1.89863109588623
2012	1.79916131496429
2013	1.80028736591339
2014	1.6811044216156
2015	1.72294008731842
2016	1.56364238262177
2017	1.61177861690521
2018	1.62839412689209
2019	1.5476325750351
2020	1.78572452068329
2021	1.79559290409088
2022	1.84312748908997