Year	Number
1960	2.896821045282835
1961	3.211657921723513
1962	3.4680168274754037
1963	3.3811146118221207
1964	3.3605659699545565
1965	2.997706423363487
1966	2.3479925783090474
1967	2.185871753275636
1968	2.30061366451312
1969	1.9099206713476014
1970	2.76514098564577
1971	2.9794244767291014
1972	2.8972697525259212
1973	2.547557067591034
1974	2.3005122464347685
1975	1.8184432373050714
1976	1.7051657504749071
1977	1.494019958570933
1978	1.565404732003527
1979	2.1419493065470294
1980	2.0873219352486134
1981	1.3598085815106282
1982	1.6588670810877018
1983	1.4002385843210097
1984	0.9380474530118673
1985	0.9404500361869271
1986	1.0826393510897125
1987	1.4516512265264518
1988	1.6787235524741406
1989	1.5302996570385743
1990	1.5373533189105788
1991	1.3627373721321445
1992	0.9441941893243055
1993	0.8880178797320102
1994	0.7573116571068911
1995	0.8117816442469078
1996	1.0328242459918129
1997	0.7946608755601868
1998	1.0144402554677838
1999	1.1264867476585236
2000	1.1612986663794735
2001	1.31951370457923
2002	1.4362408296047986
2003	1.2813201017415237
2004	1.0675140794151647
2005	0.883794061681327
2006	0.834629965214521
2007	0.8786694437927335
2008	0.8815369441567305
2009	1.3608078873744236
2010	1.172952701174551
2011	1.1911660386350473
2012	1.1948601422582463
2013	1.255177044907103
2014	1.2991868413795529
2015	1.5439294501743046
2016	1.6507959032309334
2017	1.5959135733104233
2018	1.4350347814826163
2019	1.4477587930916742
2020	1.7606941060419137
2021	1.727643613458035
2022	1.4767631681210203
2023	1.5816039597861917