Year	Number
1976	2.8057321532544
1977	1.6411746810414705
1978	1.1101384565175907
1979	0.8573201796230794
1980	1.885426047199365
1981	0.8844735097171293
1982	1.1264633374045452
1983	0.6951271098415938
1984	0.7158689034744512
1985	0.7882687168623566
1986	2.1369185982975694
1987	3.5348032993690315
1988	3.5732159303512074
1989	3.9957000666077653
1990	4.579788283070402
1991	5.590888746774427
1992	4.810625281011508
1993	4.330831734520445
1994	3.89376882830678
1995	4.216540135850277
1996	3.8232389224115835
1997	3.0960067203707977
1998	2.539162651483133
1999	3.1035408331439447
2000	3.958642148657627
2001	3.7659983126686503
2002	5.216674634918114
2003	6.040711716121226
2004	5.351572345912463
2005	3.841626373276309
2006	3.1104468908418093
2007	3.7778804961288848
2008	3.1022844695050646
2009	5.039511316355316
2010	2.761873289874356
2011	3.8440241413896907
2012	4.062921103498809
2013	3.240667288073183
2014	3.1944410519653554
2015	3.882468947246035
2016	4.197482153163345
2017	4.079175626575289
2018	5.288314350530834
2019	5.608884057163772
2020	7.353569594626422
2021	7.408661028905505
2022	4.651113699245376
2023	6.226921059081415