Year	Number
1975	6.2855743655862115
1976	5.166826933094922
1977	5.353396857637351
1978	5.3156791767649825
1979	6.694078325444157
1980	6.1965381073876955
1981	4.728455923898257
1982	5.362831047294602
1983	4.924040830870608
1984	4.387907145437225
1985	4.957131454294426
1986	5.65141801035581
1987	6.535296492880789
1988	5.129291476580288
1989	4.767103222351441
1990	4.383261785575806
1991	4.521812979990652
1992	4.052710968993159
1993	4.275406627668098
1994	4.262273520521884
1995	3.701939560933124
1996	4.008316631966579
1997	3.9481326582782996
1998	4.263555231947105
1999	4.8574487878676695
2000	4.83838294323166
2001	5.857073223756534
2002	6.974040269064001
2003	8.85034107061224
2004	9.368011688759381
2005	9.23059697901293
2006	9.394045346792787
2007	9.812812940083017
2008	9.677683720218214
2009	11.844325213207355
2010	10.502652875375805
2011	10.297918289184468
2012	10.895425371785459
2013	11.525895117524271
2014	10.884059011881915
2015	11.520969137798717
2016	11.779181922310629
2017	11.24230927320797
2018	10.389013622886804
2019	10.8709911822822
2020	13.351021511289973
2021	11.142078774655518
2022	9.172678695051047
2023	9.067029280406569