A second and unrelated source is consistent with the state-level Mass attendance estimates made in "Midwest Mass Attenders Outpace Rest of the Nation."
As it was noted in "Searching for Mass Online" one can use Google Trends to view how frequently Google users are searching for particular terms. This post had noted the trends in searches for "Mass times" closely mirror what one would expect from the Church calendar.
Google Trends can also zero in on where searches are coming from. See the screen shot below: