Year	Number
1975	2.9497249071708107
1976	4.484179708608589
1977	4.795567096365321
1978	6.773181373624504
1979	4.14363051479129
1980	2.2759387173630454
1981	2.3089366431994396
1982	1.2060511456360528
1983	1.7495909696905187
1984	4.731646639544643
1985	4.688282676135669
1986	3.217684699023794
1987	3.2269486516120858
1988	3.3388383134453044
1989	3.0534049847512885
1990	2.9297685435826
1991	2.90417921149638
1992	7.6823572077279705
1993	8.324470418448014
1994	8.500571894886347
1995	7.990606583644231
1996	8.640010928852666
1997	6.368622902754643
1998	5.357952213536223
1999	4.997225900782235
2000	4.141534159651722
2001	4.44144456291017
2002	5.369114628377603
2003	6.808182139502739
2004	6.0189774616750205
2005	5.017654894880271
2006	6.6063279497003835
2007	10.753562152323283
2008	8.331422328952316
2009	12.965831888125072
2010	10.22806088851006
2011	10.526578463723505
2012	11.630953011388533
2013	11.20498710234097
2014	11.34740435369618
2015	14.648248845814749
2016	16.603385579213032
2017	14.861068497700032
2018	13.164406843753198
2019	12.12636678658376
2020	14.772617916012193
2021	10.971620804708047
2022	8.243468471974335
2023	9.374171122245818