Year	Number
1960	0.8103281722675597
1961	1.5714276167024332
1962	1.768381674511316
1963	2.47981293859817
1964	3.3834254754401414
1965	3.194038124294149
1966	3.9960668461757853
1967	4.486186273638951
1968	3.55483622668481
1969	5.301995505853528
1970	9.834729209585532
1971	10.693926881461115
1972	4.825012840911581
1973	3.5253699977738795
1974	6.1603003266581675
1975	5.010310596078077
1976	7.10565518355719
1977	4.792223028374843
1978	2.7422660178695253
1979	2.1096176884961544
1980	2.5024013606574473
1981	2.6057538228719803
1982	2.2039219917245543
1983	1.5745506660030726
1984	1.1921849215531222
1985	1.1111079459498594
1986	1.2422823519677955
1987	2.173644548370166
1988	2.4697034272665395
1989	2.0380651701213526
1990	2.6925506432411876
1991	1.5949639101532054
1992	3.1999637683310658
1993	2.290196172091702
1994	1.7789188419874442
1995	1.740544294000509
1996	1.5349612793684846
1997	2.6602630241315235
1998	3.7447023419402363
1999	3.4773211448294163
2000	4.543458307834126
2001	4.445643061638618
2002	3.3065771949483893
2003	1.6119394250590806
2004	1.6609598259140246
2005	1.8186506817280774
2006	2.0958665984658706
2007	2.878225394345978
2008	3.910116560856683
2009	1.9930502855782382
2010	1.8488571975695447
2011	2.032088909028885
2012	2.147488632513071
2013	2.468214322505083
2014	2.3279746394049114
2015	2.2085042355082014
2016	2.5159808247092177
2017	2.194733217607837
2018	2.6863944392234393
2019	2.38464665514804
2020	2.73784261751812
2021	2.5448202198842527
2022	4.4922203178111895
2023	6.655758338185162