Why bother with a trigger and counting alive units when
all you really seem to need is a "killed" eventHandler?
Attach a "killed"-EH to all your civvies (if lots of them, use a trigger covering the whole map to round them up in a nice array), and have the EH count the number of killed civvies and display titleTexts for you.
If you still dont want that, use something like:
in init.sqs:
civnum = "alive _x" count myCivvieTrigger
and in your repeating trigger checking for civilian present, called 'myCivvieTrigger'..
condition: civnum != "alive _x" count thislist
activation: x = "alive _x" count thislist ; titleText [format ["another %1 civvies died", x], "plain.."] ; civnum = x
Or something along those lines (SNG).
(edit: I read the post more carefully the second time)