Year	Number
1976	1.037997774888191
1977	1.0044339344951791
1978	1.1810183316836458
1979	1.1809464810706123
1980	1.4073047586216374
1981	1.4584613391328294
1982	1.353979582495898
1983	1.2093380592099634
1984	1.2110003774995872
1985	0.9517752188806606
1986	1.2291319024416185
1987	0.9631149308788588
1988	1.02181289461109
1989	1.1255113767000207
1990	1.3526045524226231
1991	1.7152872328410922
1992	2.0098329367631402
1993	4.232484882009044
1994	6.396154096430442
1995	8.863085881133896
1996	12.338473930017319
1997	17.159456875683297
1998	38.56426662281076
1999	8.168708908108682
2000	12.309782992886573
2001	8.134068264134017
2002	5.757128251222322
2003	6.242777954985552
2004	5.055192831811722
2005	4.682622069322463
2006	3.8178279629954206
2007	3.2203231077413186
2008	3.737713010887204
2009	3.306937254948908
2010	3.4874368128156017
2011	4.3244524521633725
2012	3.803889841178427
2013	3.48191244015
2014	3.4818296311153905
2015	3.1931399616603033
2016	2.9782399030924065
2017	2.999301783069798
2018	3.2438348755311144
2019	2.7396835160221267
2020	2.9040532613264287
2021	2.967464926266735
2022	3.048949151055682