...Don't pick at that, it'll never heal...
7% over ten years ain't that much, really. A steady improvement, sure.
That's only one side of the system, we'd also have to compare that to the rate of natural ozone generation over that time period. And as I recall (citation needed), the halocarbons take time to rise to the atmospheric level of the ozone layer. It's not my field, but I'd suspect these would be some of the variables in the big atmospheric picture.
Are any of these other halocarbons more effective than the average at destroying ozone?
Add to that the complicated atmospheric mixing at the poles....