It would be a reasonable starting position to consider that if these three items are bringing in the most, then we should make sure we are collecting the right duties on those items, always remembering that part of the problem on duties is knowing what is coming across. It's easy to enforce a duty when you know that footwear's coming across the border and what type of footwear it is. When what's coming across the border is a kit, which is actually some type of footwear, but they've just called it a kit or something like that, that's really where it becomes more difficult to make sure the rules are being applied.
It's not so difficult to make sure the rules are being applied when everything is being properly coded and classified and paid. That's easy enough. The difficulty is going through all of the details to find the things that were actually shoes, but weren't called shoes, and then making sure that the duties apply.