Year	Number
1960	1.868782495447559
1961	1.9454236531602531
1962	2.075671337891708
1963	2.145906256020422
1964	1.9491536258194535
1965	1.2875899483459081
1966	1.2695339676247694
1967	1.0799866533811657
1968	1.0499149281129436
1969	1.2667238200052886
1970	1.4053057453310627
1971	1.4684673085478555
1972	1.4022945426061644
1973	1.4906739791125359
1974	1.4837553138178134
1975	1.6007897881070217
1976	2.0163768033011586
1977	1.8545630731250586
1978	1.8599056118590898
1979	1.6127359379612725
1980	1.8858793789521617
1981	2.370967470996285
1982	2.897451744200484
1983	3.5936458311940864
1984	5.444915310172716
1985	6.186353125343509
1986	6.963049919164125
1987	7.808275956328092
1988	17.91137106199065
1989	7.311954535186645
1990	4.637989448151799
1991	5.396683216316053
1992	5.990375982792396
1993	3.2509402748641456
1994	3.2469512915609737
1995	2.9983455922231546
1996	3.2579713706949844
1997	2.958067543094032
1998	3.8529621603219755
1999	3.194259791350698
2000	2.767167666989017
2001	3.2431595028801325
2002	2.715621212929208
2003	2.4294606616382133
2004	2.6437738218381703
2005	3.201383894038686
2006	2.8254013802936613
2007	2.7985781890339467
2008	3.008553473748178
2009	2.7468444517168376
2010	2.6705716362999654
2011	3.0913759759030532
2012	4.147684564822303
2013	3.024090437442139
2014	2.4970852653536224
2015	2.6003449396409106
2016	2.8928146074607657