Lens recommendation based on current usage

Good approach - having a look at what you actually use in order to determine what to get next.

It looks like your "bell curves" both start kind of in the middle (the high point of the bell assuming you would have had a normal standard distribution of both FL and Aperture). That probably means that you would like both wider angle AND bigger aperture. There aren't a LOT of choices that have both, but there are a couple...

The Canon 17-55/2.8 gives you one more mm on the wide side and constant 2.8 aperture throughout the FL range that comprises over 90 percent of your shots.

The Sigma 18-35/1.8 gives you wider aperture in the focal range that you seem to use a lot

The Canon 10-18 IS gives you a lot of coverage in the wide area... if you usually are usually using wider apertures to get higher shutter speeds to avoid blurred images due to camera shake, this one might be a good choice, as even though it is wider aperture it is short focal length (which decreases the need for faster shutter speeds to avoid camera shake) and it has IS, which will help some. If you usually use the faster aperture to freeze subject motion or for shallower Depth of Field, it might not be the best choice.

I think Tokina makes an 11-16 f/2.8 lens that looks interesting...

I see that you don't really have a big spike at 40mm, which it seems that you should if you really value the f/2.8 (considering you have the 40 mm f/2.8).... either that or the pancake lens is a recent purchase.  You do have a big spike in the short focal length range and the wide aperture range, so that indicates that you use  the 24/2.8 a lot.

The best choice depends upon what you feel you are missing.  If it were me, I would probably get a UW such as the 10-22 or the 10-18IS... but if you feel like f/2.8, or wider, would be of more value to you than you should go with a prime and see if f/1.8 or f/1.4 becomes your new most favorite aperture.