Year	Number
1975	1.8313002822982718
1976	2.3657986474577277
1977	1.4894805364006485
1978	2.621666983930462
1979	3.4366230048485296
1980	3.565435316022342
1981	3.4094433636789754
1982	2.6691271735545086
1983	2.109077744462875
1984	1.8437792917918687
1985	1.1937218577679494
1986	0.8654359154140567
1987	1.3953151525186347
1988	1.1034949301927857
1989	1.737721994039958
1990	1.2324448095630618
1991	1.4706004169541922
1992	1.1640646629856328
1993	0.8619185512499402
1994	0.9104573513600128
1995	1.929810355728277
1996	2.8005736875803686
1997	4.399245580315546
1998	1.2366185583569511
2012	2.6130328693221316
2013	2.746522668999781
2014	1.994839129818901
2015	3.4668281963432754
2016	3.797288572612401
2017	3.4936887501508926
2018	3.2950184053054867
2019	3.193386459491191
2020	4.636161381433737
2021	5.413780651785683