Checking a larger subnet than I normally do; mapping out a cluster suite in a university for a traffic mapping project (permission attained), and I was wondering something.

NMap usually prints its progress periodically, but I'm unclear to what that 'periodically' is, because the cirrent scan printed a line for basically every 100th of a percent up to 1% done, then one at 1.5%, and has said nothing since.

I suspect that it changes at different 'levels' but does anyone have an actual answer?