Is there an iPhone app available that lets me track data usage on a per-app basis? I want to see which apps on my iPhone are using the most mobile data. I know I can do this in Settings > Mobile Data, but the list I get there is cluttered and in alphabetical order. I want a list of apps that I can re-order, so the apps using the most data are at the top of the list. Is there an app that does this? My Data Manager doesn't seem to (although it is great for other things).
Since version 4.3.0 of "My Data Manager" (see screenshot) that app does not track usage based on which app that use the data. According to the version description it was due to a change in the App Store guidelines.
If "My Data Manager" had to remove the feature I assume that all other apps also have to remove it.

If I remember correctly it was something about not showing other developers apps in your own app, but I could be wrong.