Year	Number
1962	2.239862050154005
1963	2.611376682577481
1964	2.4053767684305414
1965	2.63206592893334
1966	2.767442132442326
1967	3.843541305849455
1968	5.781892395421641
1969	9.477527535242727
1970	5.350789929191264
1971	4.558817131747466
1972	4.970421810811396
1973	4.494432521027541
1974	6.9099389568213
1975	10.979486680151258
1976	9.63624963362753
1977	6.514740161355128
1978	9.549835167959637
1979	131.20668892809326
1980	88.22623983874227
1981	29.169224276747475
1982	32.793297867338204
1983	16.541615083874976
1984	7.598968780695377
1985	9.109115232712302
1986	4.741202087538279
1987	2.196749533940052
1988	1.6918548250704417
1989	1.810499649981527
1990	5.4068360676831855
1991	5.980501617296733
1992	7.577293340207949
1993	9.59778010839724
1994	10.283119036769387
1995	5.650064288350367
1996	3.1126437372939204
1997	2.5662338987327287
1998	4.189401647938895
1999	3.2614952910527855
2000	2.8263428521121035
2001	2.573615957567237
2002	2.938107770612537
2003	3.0934115989293014
2004	2.1117865731296055
2005	2.1076809728353996
2006	2.129129632293974
2007	2.0338474919477068
2008	2.1581583796583272
2009	2.0758259018447434
2010	2.0846185503428662
2011	2.2683261148009963
2012	2.4260507576534325
2013	3.392412120291761
2014	3.4448549136198503
2015	3.073299459856426
2016	2.3635777258762807
2017	2.1048833114710943
2018	2.0255792751710517
2019	2.0518828461416283
2020	1.860594625930147
2021	1.7320103343675153
2022	1.9910081177631116
2023	1.635205982058749