The expectation is that there are at a minimum 15/20% dead under the bombed and decimated buildings. It could well be much, much higher, even double, or triple is not infeasible, given the large scale untargeted bombing, population dispersement and recognised IDF tactics that don't allow for groups to even consider searching and rescue operations in most cases but leave possible survivors buried under the rubble to die slowly and horribly.
The current numbers are just not even close to verifiable given the circumstances, but are statistically clearly far worse in terms of civilians on all measures.