I don't think I've ever seen that figure published. However, if you were to base it on a random selection of dealership inventories, I'd have to guess that there must be at least 5 or 6 SLTs to every SLE made. Maybe even more than that. SLE's severely limit the number of options available, so I'm guessing they don't build as many by default.
I'd be interested in seeing the numbers. GM as with most car makers historically sell more "base" than "upscale" models, but perhaps this is different with SUVs/Crossovers. I've noticed the same thing re: options, so I'm sure this steers buyers to the SLT if they have to have a certain option like the DVD player. This can also work in reverse, with the Outlook I like the (base) XE over the XR since I don't care for woodgrain on the trim and dash.
I'm learning a lot from this forum and the Outlook forum and will be able to get by with a "base" Lambda and add-in the stuff I want such as Nav & DVD.