One could like infer a number mathematically by referencing deaths of women and children (14 and below, as otherwise people will say they are child soldiers). I agree these numbers are not enough though, which is why Israel should allow in UN monitoring agencies and others to create that more full picture. Also from the article:

“The numbers may not be perfectly accurate on a minute-to-minute basis,” said Michael Ryan, of the World Health Organization’s Health Emergencies Program. “But they largely reflect the level of death and injury.”
In previous wars, the ministry's counts have held up to U.N. scrutiny, independent investigations and even Israel's tallies.

It released its first detailed report on the casualties Thursday, giving names, ID numbers, ages and gender for Palestinians it says have been killed.

So, while imperfect it still is obviously the best and only resource at the moment. Perhaps Israel could start going through those lists and letting us know which ones matched to their database of terrorists?