Year	Number
1975	9.19319075468994
1976	10.435161393128693
1977	12.55717703518221
1978	13.528138728802046
1979	11.73901248657691
1980	11.355165810491359
1981	13.38037369155672
1982	10.205811991902209
1983	7.289897433253448
1984	5.455944744799093
1985	5.238971863709248
1986	2.7894214331376834
1987	1.3929019296282212
1988	0.9730062357307138
1989	1.6979864897143697
1990	3.302713414686043
1991	1.9200749411644682
1992	1.121406453041212
1993	1.5336711140835528
1994	2.3036550037070413
1995	1.7651928770189738
1996	2.467031964609967
1997	2.361197293342786
1998	2.623428728187327
1999	3.3254832138269665
2000	3.8228700778638602
2001	5.024869430008528
2002	5.356968283605683
2003	5.9048255801912015
2004	6.710350984372767
2005	8.400703239925695
2006	9.822810903298116
2007	8.720106910020839
2008	9.964449764812773
2009	12.225610079132
2010	13.354655019731947
2011	8.456294069265606
2012	7.6868265287070825
2013	8.779608142903173
2014	10.80277107567117
2015	10.615250290771677
2016	10.626642016222243
2017	10.120917220637368
2018	8.733913794852972
2019	9.051705980233285
2020	9.980531139392879
2021	8.722926393578561
2022	6.3176943730116735