Year	Number
1976	6.484320929258791
1977	6.359721560530451
1978	6.895533961372321
1979	8.571644435680273
1980	7.263309407403256
1981	4.871843318012926
1982	5.592966502150873
1983	6.09006893302752
1984	5.531838693917443
1985	5.586518635616972
1986	5.586693833537933
1987	5.906342791792574
1988	4.438749495866216
1989	4.432302820522538
1990	5.670310582591904
1991	6.271209071584004
1992	5.52494334888557
1993	5.880313854259878
1994	6.214344669804734
1995	5.7459183193819126
1996	6.389766757275261
1997	8.09352894198138
1998	8.334008093648725
1999	8.113740620794314
2000	7.19871881156392
2001	8.120973902167197
2002	9.622756589040709
2003	9.085604449776572
2004	9.807047774306643
2005	10.885662627726836
2006	12.45043470210578
2007	14.632654218695347
2008	14.34799455840885
2009	19.17721532255563
2010	16.924756254034758
2011	15.87195700120175
2012	15.189813785924374
2013	15.386062846080439
2014	14.787363782318266
2015	14.626892357599496
2016	14.171486494500547
2017	13.020196383514074
2018	11.400103941167279
2019	11.678101836258115
2020	13.752336381651487
2021	10.655575470371998
2022	9.545895938426444
2023	10.239613181805506