NB.SI($A$4:$A$7077;"somme*")
=SOMME((FREQUENCE(SI(SOUS.TOTAL(3;DECALER(A3;LIGNE($A$3:$A$7076);0))*($A$4:$A$7077<>"" );EQUIV($A$4:$A$7077;$A$4:$A$7077;0));LIGNE($A$4:$A$7077))>0)*1)-NB.SI($A$4:$A$7077;"somme*")
=DECALER(Janvier!$A$3;;;NBVAL(Janvier!$A$3:$A$500))
=SOMME(1/NB.SI(Date;Date))/2