Year	Number
1996	1.70890808105469
1998	1.54505217075348
2000	1.38453423976898
2002	1.36862599849701
2003	1.41381525993347
2004	1.27040612697601
2005	1.58444654941559
2006	1.70114398002625
2007	1.7392373085022
2008	1.73599350452423
2009	1.75030028820038
2010	1.68115770816803
2011	1.55607664585114
2012	1.45570015907288
2013	1.64609754085541
2014	1.69248104095459
2015	1.67384648323059
2016	1.64932882785797
2017	1.52917754650116
2018	1.5346816778183
2019	1.45883345603943
2020	1.53513503074646
2021	1.61967813968658
2022	1.67444837093353