Why exclude rims narrower than 22mm? Do they, at that width, abruptly become so inefficient that they cannot be considered 'aero'?
Surely you have to include all non-box section rims, regards of width, to get the full picture?
I don't think that deep narrow wheels are not more aero than box section, but they truly struggle standing up to today's wider wheels. This chart for instance shows a lot of the new wider wheels such as FC 808, Bontrager 7 D3, Mavic's new CXR and their CC80; as well as a Hed Jet 90(20mm brake track) with a 20mm tire.http://www.slowtwitch.com/articles/imag ... raph_2.jpg
As you can see, the only place that the Jet 90 is competitive is at 0 degrees yaw; at 5 is close and from there out it really isn't with the pack except on the non-drive side it doesn't stall until later than some of the competition.
To give you an idea of how this all compares. I've seen data on the PX 101 rim, where its faster than the old 404 shape over a range of yaw from 0-20. Nowadays, we're seeing the 303 be quite a bit faster than the old 404.
So a well designed 44mm rim can be faster than a non-designed narrow 100mm rim.