Year	Number
1966	6.681798348465016
1967	5.309607958614581
1968	4.1489394710003955
1969	4.854473180265035
1970	4.433381964821643
1971	4.313421051797171
1972	4.495267945623557
1973	3.5692447860510765
1974	2.696192116799444
1975	3.6162801168135488
1976	4.399181109616281
1977	4.694835858162958
1978	3.964941467262786
1979	2.8073994238651467
1980	2.315630118168768
1981	3.1631625187146724
1982	2.9552717158868145
1983	2.9495019485807568
1984	3.7849670538453286
1985	3.892969731929409
1986	3.637224383189755
1987	3.6711577265740036
1988	4.111756233792796
1989	4.374607046693083
1990	3.9256674911183747
1991	3.981188526876917
1992	4.254008121876428
1993	4.489997269420714
1994	5.218024856639633
1995	6.03556418656408
1996	6.87691876468977
1997	7.094002861987624
1998	6.053399995010829
1999	5.449880279242878
2000	6.791396308722467
2001	8.29903533133824
2002	7.5670216884610815
2003	4.255500916739903
2004	4.44416049462164
2005	4.761722430731603
2006	5.6104573761629535
2007	4.332218221463865
2008	5.056814411919938
2009	3.142371083795483
2010	2.3322697846681857
2011	5.065912177260992
2012	3.1545795644551102
2013	2.9750462829851134
2014	3.204140181294576
2015	3.844514325998245
2016	4.2866204163592005
2017	11.044346304620813
2018	5.103953473098054
2019	3.997943557756036
2020	4.022310625913265
2021	3.9602071737815985
2022	4.141991146681101
2023	3.8520883091054996