Year	Number
1974	4.440608145653729
1975	1.8233263391375256
1976	1.2082826748308586
1977	1.086587767057014
1978	1.1598341565642825
1979	1.228666129865821
1980	1.0814359109843676
1981	1.6710939267631655
1982	1.9524492322063611
1983	1.922719950537344
1984	2.0197030748817144
1985	1.577411805834559
1986	1.4787845257272076
1987	1.43586081961637
1988	1.6023111676270276
1989	1.3530185720253942
1990	1.1511864587944078
1991	1.6309173640370713
1992	1.064811417256422
1993	1.2341730414279966
1994	1.1207048893181442
1995	1.1348440978559653
1996	1.3075735716392711
1997	1.2549934731002421
1998	0.970753191994984
1999	0.9688953165300106
2000	0.8512676365311865
2001	0.9746735213237903
2002	0.8881726931899385
2003	1.407807226817916
2004	1.5131443579145338
2005	2.2371782458187073
2006	1.720564972002975
2007	0.966539449543237
2008	0.9792420864146724
2009	0.9493035668724449
2010	1.5030137552485523
2011	2.0132285371862566
2012	1.5876091767090637
2013	1.5208315379378792
2014	1.552537965339705
2015	1.8925123348898405
2016	2.012817680809138
2017	2.3105417945048026
2018	3.093143502141463
2019	2.886636060653627
2020	2.359979243981063
2021	2.5133619712026354
2022	2.9769316234240915