Year	Number
1960	3.2839674830922587
1961	3.041004547553977
1962	1.8270195232367137
1963	1.7468546717066145
1964	2.0360400363977926
1965	2.005655388477724
1966	2.4302154382767207
1967	2.6718622964138854
1968	3.4523691362365874
1969	6.5023518319992615
1970	7.123787959454796
1971	4.322006117362297
1972	2.2218733755392375
1973	1.805467670722224
1974	3.5604915807697886
1975	3.4226829667396976
1976	3.1581879008461726
1977	3.5532930973707497
1978	1.2878786096745125
1979	1.0807018763110745
1980	1.1705780587295194
1981	4.970022949956657
1982	5.16581688024503
1983	7.356986593258254
1984	10.299491520162624
1985	5.783759344902872
1986	4.391034657892074
1987	4.13949105108169
1988	7.250160699927839
1989	5.711801497439707
1990	5.585312445689255
1991	5.970885312874041
1992	8.768588621034263
1993	7.46544881300322
1994	8.21554186466032
1995	8.362541234219018
1996	7.015237358039636
1997	4.189796181179941
1998	4.080983518378502
1999	4.341602609841522
2000	4.623272885291367
2001	4.847771632542785
2002	4.63886833700728
2003	4.413666281270793
2004	4.670639316995838
2005	4.956146029130922
2006	5.138000251473098
2007	4.533046470343347
2008	3.917478057947786
2009	2.652303725207121
2010	2.4591018095509494
2011	2.714729122676761
2012	2.6414127438465425
2013	2.841265145036468
2014	3.0456961686428805
2015	2.7775210956884093
2016	2.8211001123938027
2017	2.674550767550973
2018	2.73935980166005
2019	2.713845444233197
2020	2.493304287511234
2021	2.4953455795975352
2022	2.8031805446436957