Year	Number
1960	0.9889545746815517
1961	1.1269544710213395
1962	1.1966852384638416
1963	1.1114968991409926
1964	1.0092656070697468
1965	1.064716779642832
1966	0.9889944252691097
1967	1.0839779520122281
1968	0.9520464781708476
1969	0.7606451594925484
1970	0.5200496955865924
1971	0.4513234263062401
1972	0.5267286020988136
1973	0.9761025370239137
1974	0.8965611784077524
1975	1.5298901646989045
1976	1.4094186369485346
1977	1.1705579326313444
1978	1.498204052713743
1979	1.2466592111097494
1980	0.8055963154881095
1981	1.3330032836380499
1982	1.472234320095684
1983	1.8464309476652758
1984	2.5589678699426126
1985	2.1849014543167375
1986	1.8468620390588137
1987	1.9773287503959194
1988	2.5380324380047736
1989	2.7084860790555223
1990	2.7257901202425305
1991	2.8200554476419093
1992	3.091846642778165
1993	3.8015730235270353
1994	3.7326770982024664
1995	3.376328205062406
1996	3.2640593447343464
1997	2.9930664943362184
1998	2.135953839412121
1999	2.3063090893013576
2000	1.3522029510474487
2001	1.019596907511661
2002	0.5214835904049501
2003	0.40706564754180385
2004	0.353968515323524
2005	0.30024577579493383
2006	0.2296031564310608
2007	0.246444810470525
2008	0.3279240258711565
2009	0.34894630602709276
2010	0.33558385682871805
2011	0.413500318684397
2012	0.40056254054195495
2013	0.43982433625175776
2014	0.5602239625816626
2015	0.7000263189257682
2016	0.9391199619259756
2017	1.0328656664386584
2018	0.9753872208928948
2019	0.9419284966129562
2020	1.1610805982080277
2021	0.27576231704696097