Year	Number
1960	16.590534944684148
1961	18.7496978836718
1962	22.287077499695567
1963	24.903179448970082
1964	27.40098504477022
1965	32.12005541347854
1966	34.86172880036901
1967	38.585160660533276
1968	35.019471159499986
1969	37.06926071208642
1970	46.07076901400253
1971	53.93527412251009
1972	44.16447562242218
1973	29.702830798229584
1974	19.383843889176
1975	27.56530446611526
1976	29.686429326046454
1977	27.518731875986916
1978	23.533346157586728
1979	12.525427181545682
1980	11.586143122156187
1981	17.96192127325026
1982	17.072019062370902
1983	21.53718310859957
1984	28.455785039387045
1985	27.387268909579994
1986	25.264833739270195
1987	22.739119120379343
1988	27.241188925342936
1989	24.536140533407327
1990	24.536793205583646
1991	27.06606927800244
1992	29.176488583637994
1993	26.30272441280735
1994	26.5753749772564
1995	26.399089352913602
1996	31.193539101180804
1997	40.14252619600381
1998	40.631024500534465
1999	47.61051044365872
2000	54.699209045550674
2001	58.277166755652615
2002	50.189226820794275
2003	44.921685246797644
2004	45.89488600392529
2005	50.18132980589673
2006	46.5767728339338
2007	41.44785223523808
2008	42.32082605871619
2009	32.49268231673325
2010	26.116024004717104
2011	25.35472396194284
2012	24.88381160594555
2013	33.29518387261568
2014	36.15539079721815
2015	42.217735480748715
2016	41.44371385375694
2017	39.06981367664842
2018	40.7689952089237
2019	38.477842916529504
2020	37.081748650884336
2021	38.02100919543272
2022	38.20783612530221
2023	35.5288738507777