Year	Number
1996	1.77176654338837
1998	1.62870609760284
2000	1.58685111999512
2002	1.6784462928772
2003	1.76194429397583
2004	1.9400452375412
2005	1.74136209487915
2006	1.58340215682983
2007	1.65778410434723
2008	1.66906487941742
2009	1.84807932376862
2010	1.81132459640503
2011	1.87170588970184
2012	1.79215371608734
2013	1.75041556358337
2014	1.92541670799255
2015	1.8537882566452
2016	1.80650162696838
2017	1.72768080234528
2018	1.6288366317749
2019	1.63260245323181
2020	1.53899621963501
2021	1.30689489841461
2022	1.34053194522858