How to Divide Multiple Counts?

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I've been stuck with this problem for a few days and have searched fairly extensively to no avail.

I have a series of columns that are counting IF statements.  For the final column, the idea is to count all of these IF columns then divide them by the count of unique incidents along the lines of;

count(if(incidents.c$enq_chnnl_cst_bol=1,1))+count(if(incidents.c$enq_chnnl_outreach_bol=1,1))+count(if(incidents.c$enq_chnnl_other_bol=1,1))+count(if(incidents.c$enq_type_online_bol=1,1))/count(*)

This doesn't seem to work (see screenshot) and either does replacing count(*) with count (distinct incidents.ref).  I think i'm approaching the logic wrong here but I'm damned if I can work out what I should be doing instead.