Year	Number
1976	5.213031104678691
1978	6.4765532919069315
1979	6.3560554326452205
1982	6.872209047753434
1983	6.921402363026161
1984	5.932783838311519
1985	4.625972054736018
1986	5.005390951184723
1987	5.422926007642047
1988	4.462532619886148
1989	4.280668159266586
1990	5.7479771310038075
1991	6.842663456300925
1992	5.487678595453091
1993	5.661954902626348
1994	5.872929314643238
1995	5.617235797777017
1996	6.267921624681151
1997	9.130939538801803
1998	9.438664628769512
1999	8.889187512773038
2000	7.420420954815962
2001	8.674580412192622
2002	10.59590078176549
2003	9.012863181346919
2004	10.188718699659896
2005	11.251381329216859
2006	12.503962452794745
2007	14.76175173002453
2008	14.776892435897732
2009	20.51942429317926
2010	17.84268564183378
2011	15.699362873369322
2012	15.659820773458248
2013	16.126325095682986
2014	15.753616405044145
2015	15.454561674993867
2016	14.693296599266086
2017	13.562963423984801
2018	11.796061360262591
2019	12.31180371749152
2020	13.891282964273037
2021	10.930362051100731
2022	10.292825065409334
2023	11.154196788813742