Year	Number
1996	1.94293475151062
1998	2.00421094894409
2000	1.9833756685257
2002	1.93344473838806
2003	1.95480120182037
2004	2.07049989700317
2005	1.93773639202118
2006	1.78492248058319
2007	1.72176647186279
2008	1.68715620040894
2009	1.73591732978821
2010	1.77032697200775
2011	1.82099711894989
2012	1.83936905860901
2013	1.80927610397339
2014	1.83621108531952
2015	1.82900989055634
2016	1.82077288627625
2017	1.81359350681305
2018	1.80971109867096
2019	1.76726531982422
2020	1.80571496486664
2021	1.72705924510956
2022	1.57946932315826