Year	Number
1964	2.1138980911815746
1965	1.7829195790150236
1966	2.2256493506493507
1967	3.704893917963225
1968	6.5400400495620215
1969	2.691771550593499
1970	1.655058947710227
1971	1.761437772638142
1972	1.649848267506488
1973	1.8131134307606482
1974	3.2667149460807052
1975	1.4629573088040935
1976	1.271309791140137
1977	0.7928110983473542
1978	1.1762844533169154
1979	1.095510042084111
1980	1.0469621639713562
1981	2.0941850167691607
1982	3.6253556631356267
1983	5.080743932735692
1984	5.4348890263662435
1985	4.685682377380333
1986	2.296860308465504
1987	2.3687193526096095
1988	2.179242087164784
1989	1.6455389105031508
1990	1.5996368143674622
1991	1.3485339636271705
1992	1.0178043621334558
1993	0.9807738081979074
1994	1.0071068186574188
1995	0.9167663968121433
1996	1.3296424328700314
1997	1.5319161648590882
1998	2.0018210332436563
1999	3.1226690439716656
2000	3.9707771088993153
2001	8.402639667162347
2002	2.9678291385638333
2003	2.7982555153176345
2004	3.087861618801052
2005	2.5794185070915603
2006	2.551330522872857
2007	1.8849953772346282
2008	1.5274858803304894
2009	1.4220416809306644
2010	1.7282635094165253
2011	2.028558548408565
2012	1.9696559236198057
2013	1.9268518374937247
2014	2.25699370174367
2015	5.170255893677109
2016	6.736634440220236
2017	7.644322033581344
2018	12.996988778495997
2019	9.16614917575162
2020	13.56932283815251
2021	5.188505647581066
2022	11.92457450070793
2023	16.712687032715927