Year	Number
1979	1.7085030489319686
1980	1.495815561420602
1981	1.3237574382836472
1982	0.6119326802444993
1983	2.3757376568824946
1984	3.220794538623539
1985	2.1837647248699943
1986	2.9729546734033945
1987	5.953468564646771
1988	2.071713705160182
1989	1.814373138215989
1990	2.3052881996824173
1991	3.555247801272279
1992	3.1885833570600584
1993	4.064375242712009
1994	0.8831093182337171
1995	2.8255464401457617
1996	2.7107506111689403
1997	3.4056740694692427
1998	2.4492236787244983
1999	2.2092403780572836
2000	2.01762486355417
2001	2.636899716819857
2002	2.9800698231012213
2003	3.4404658817408853
2004	3.2878272340434407
2005	3.3128817109364044
2006	2.9667795380129798
2007	3.069323167044668
2008	3.1057137617219146
2009	4.187409325900718
2010	4.053644995703648
2011	4.276308530933501
2012	4.484717176399865
2013	4.565877619718498
2014	4.8052922601245625
2015	4.460077383072961
2016	4.547940070855039
2017	4.1211993008023065
2018	3.7461136142175206
2019	3.9154153935276748
2020	5.079028287266577
2021	4.123981147786837
2022	3.327491802445578
2023	3.47921510184771