Year	Number
1996	1.2400096654892
1998	1.19578731060028
2000	1.27151811122894
2002	1.26314008235931
2003	1.17419981956482
2004	1.22550690174103
2005	1.24708712100983
2006	1.29370141029358
2007	1.32278323173523
2008	1.38836634159088
2009	1.39269268512726
2010	1.38820207118988
2011	1.38531708717346
2012	1.4102840423584
2013	1.4392409324646
2014	1.67060923576355
2015	1.65832471847534
2016	1.68796372413635
2017	1.63365566730499
2018	1.54483294487
2019	1.58012461662292
2020	1.52953481674194
2021	1.54799437522888
2022	1.5589644908905