Year	Number
1976	10.544353506857485
1977	8.557792026742787
1978	6.507369402559683
1979	8.193540831665937
1980	6.802614989924086
1981	4.593678591238312
1982	4.639057891915233
1983	4.954057299594159
1984	4.795183345158872
1985	6.227465330558028
1986	5.994238538077074
1987	6.364024154307568
1988	4.9427176225202
1989	4.616550930086744
1990	4.948656467331431
1991	4.873233720498951
1992	5.01045976357238
1993	5.514250515544673
1994	6.025291163863946
1995	5.377138212442869
1996	5.953207821910435
1997	5.742605709802681
1998	6.014377187277019
1999	6.334186079675828
2000	6.330679558459484
2001	6.628170494631592
2002	7.1341122514054565
2003	8.562933609784793
2004	8.012367004196193
2005	11.938918163543695
2006	14.459062958756615
2007	16.139945580721776
2008	17.384409166814503
2009	18.36751194056767
2010	17.675397410288255
2011	20.54859573434173
2012	20.138380151778158
2013	20.19820827069819
2014	18.018251334446248
2015	16.609644857887524
2016	17.155043947637047
2017	15.232746470951934
2018	13.957252633801463
2019	13.30423406517605
2020	16.560543287046332
2021	12.88816462191312
2022	9.934515164417089
2023	9.779280625916225