Year	Number
1976	1.8650222822711382
1977	4.0139520688766295
1978	0.9491128043111725
1979	0.6700789646360078
1980	0.1725598245438572
1981	0.16791079522625973
1982	0.04934140531439494
1983	0.25911716494612486
1984	0.3147375454647582
1985	0.1629374788785232
1986	0.5906017219115222
1987	0.2746188194472282
1988	0.6280648781967592
1989	0.4265776099003872
1990	1.389575654787217
1991	1.4205782860255045
1992	2.053040837818243
1993	1.1122566656031736
1994	2.026839815192254
1995	1.5738221467256337
1996	2.4708078241811475
1997	3.6273025907406486
1998	2.9912323669369543
1999	4.056111636004382
2000	5.35232951517447
2001	5.463851945367975
2002	8.078103000910712
2003	8.31761478545152
2004	7.308802440759381
2005	5.2975486038479564
2006	5.197167193812604
2007	5.19775259742116
2008	3.770624744070405
2009	5.195866503556626
2010	4.785125044062492
2011	3.475475749731782
2012	3.6334365550961545
2013	3.9074100806549144
2014	3.7065889623787327
2015	4.297196954207779
2016	5.2135234805212445
2017	6.828209197836952
2018	5.390793503409259