Year	Number
1960	5.391820907738724
1961	5.774820418447742
1962	12.16511613275012
1963	5.619322132316101
1964	3.152056897141542
1965	2.2671560254454417
1966	2.533583517435678
1967	2.9484913802373223
1968	3.026292219514631
1969	3.3024802949909233
1970	3.437547432095014
1971	3.340094183250393
1972	3.099568429636131
1973	1.879045385248046
1974	1.0799837440917102
1975	1.704554331745729
1976	2.393866451035882
1977	2.064506339332588
1978	2.2953395509514523
1979	1.5754090082450327
1980	1.6715388378170828
1981	2.7412004600432183
1982	2.6996980899944707
1983	2.245881479610735
1984	2.424567903886133
1985	1.3257322647831138
1986	0.828128912456314
1987	1.4615670565875132
1988	1.8332034292640227
1989	1.630558327407486
1990	2.3316388150256935
1991	3.7671668547049006
1992	4.095576690746063
1993	4.195419313756261
1994	3.4706943023665753
1995	2.837862128631677
1996	2.899761965947924
1997	3.1910482045487902
1998	3.8482571281883837
1999	3.676362397711116
2000	3.700457200706017
2001	4.509598611079065
2002	5.024993147993874
2003	4.372753450038636
2004	3.455057026182349
2005	2.7411962359188635
2006	1.9132905582989008
2007	1.48971355526823
2008	1.3868446440940114
2009	1.4178115737358798
2010	1.407870147984758
2011	1.420578298762592
2012	1.4664307823188618
2013	1.671391610281786
2014	1.8434053020240293
2015	2.418006594738778
2016	3.1386536783706003
2017	3.38740367463967
2018	4.047299423289549
2019	5.511078291869689
2020	7.40918800633998
2021	8.741694812515272