MPG with and without TT

I have the exact same car (but 2013) and tow a 21'Kodiak Hybrid 3500lbs dry with WD, sway and tranny cooler. I get around 29mpg not towing but am a fairly conservative driver, usually going around 70 (depending on speed limit) at about 2000 rpm in 6th. When I tow, I usually drive around 60 and my mpg is about 14 running around 2500rpm in 4th. However speed and wind make a huge difference for me due to the trailer being a big square wall. If I have a head wind my mpg can go down to 8 or with a tail wind up 21. Also my mpg goes down very rapidly after 60mph, probably due to wind resistance or the fact that the tranny does not often shift above 4th when in tow so at 70 I am at about 3000rpm in 4th. Driving above 70 can lower my mpg below 7. My sweets spot for the SantaFe/Kodiak combo seems to be 60mph. It sounds like your numbers and experience are roughly in line with what I am seeing.