does anyone know if the search results for the free wordtracker tool show daily/weekly/or monthly search results?

(do note, i am not asking about the full paid-subscription version of wordtracker, only the free tool that is available online, if there is a difference)

I had thought it was daily, but if so it seems too close for some keyword results to overture scores which were monthly.

it says this on the site about page:

Wordtracker periodically compiles a database of over 330 million search terms which is updated on a weekly basis. All search terms are collected from the major metacrawlers - Dogpile and Metacrawler.
but i am not sure how to interpret that. are the results for weekly searches or are they daily results that are only 'compiled' on a weekly basis?

if anyone knows i would appreciate it. thanks.