Year	Number
1996	1.86076653003693
1998	1.84430778026581
2000	1.94497442245483
2002	1.95681166648865
2003	2.03996324539185
2004	2.05234384536743
2005	1.96848773956299
2006	1.89015877246857
2007	1.78888738155365
2008	1.82254898548126
2009	1.63136506080627
2010	1.580402135849
2011	1.5774759054184
2012	1.48314440250397
2013	1.48348927497864
2014	1.48597574234009
2015	1.46154487133026
2016	1.3506007194519
2017	1.41327965259552
2018	1.4258269071579
2019	1.48212385177612
2020	1.47633063793182
2021	1.59525525569916
2022	1.56327533721924