My wife, son, and I were discussing “catalogue” vs. “catalog” yesterday, so naturally I turned to Google Ngrams to see actual usage in American English books over time. Here’s what I saw, again focusing only on American English books published from 1952 to 2008 (2008 being the latest year that Google Ngrams offers); I was quite surprised by how catalogue and catalog are roughly evenly coexisting.
The blue line is the ratio of “catalogue” to “catalog” generally, with “catalogue” starting out as the somewhat popular variant, even in American English (and much more popular still if one looks earlier than 1952), and “catalog” becoming the somewhat popular one only in the 1970s. The other lines show various verb forms, and indicate that “catalogue” was even more popular, relatively speaking, as a verb than as a noun (though not in the -ing forms). On the other hand, in British English, all the catalogue forms continue to be much more popular than the catalog forms, though the margin, while still huge, has been substantially declining.
And if you aren’t wasting your time on Google Ngrams, then you’re wasting all your time-wasting.