Year	Number
1960	17.04106164524295
1961	12.503258843015761
1962	12.507925456076903
1963	14.392714506128684
1964	12.117673063919806
1965	12.780765980927313
1966	13.230034488369395
1967	18.222774265988637
1968	19.915180877034803
1969	25.888789495230338
1970	24.66795629274236
1971	18.5665190750003
1972	14.905184521378969
1973	10.920277237859372
1974	13.470389618423688
1975	11.306447754121374
1976	13.615261642080158
1977	9.975950679693316
1978	9.311226197278042
1979	9.51214164708453
1980	10.238459497418129
1981	11.272779671358132
1982	9.389302500509437
1983	8.166053100523005
1984	9.120538872208952
1985	6.656148318536213
1986	7.963823305889152
1987	7.613223580533002
1988	8.576206114798683
1989	8.28166441424816
1990	5.364026592232048
1991	5.427110721079139
1992	4.83565405327026
1993	4.336622736166592
1994	3.6887248776832875
1995	4.067243096638389
1996	5.8456463078831336
1997	8.873847568571405
1998	6.6945529186044705
1999	6.450558510541505
2000	6.018834484391338
2001	6.901723772115798
2002	6.460051148921431
2003	7.023718619165997
2004	7.15023165356456
2005	8.157776200341772
2006	8.43547917924466
2007	9.859130530827237
2008	10.84100476510388
2009	5.902594384060748
2010	6.354416950070121
2011	7.227268092463465
2012	6.881960348552123
2013	5.939553950416765
2014	6.136263482371297
2015	5.733495890677954
2016	6.017232850170654
2017	6.33116089484569
2018	6.63774497421745
2019	7.125666802084309
2020	8.236365580561595
2021	9.17194557581705
2022	7.711902612466669
2023	7.664732339649326