The study looked at TUEs in the ADAMs database, which should include all TUEs, regardless of competitions.TUEs aren't tied to a competition. For inhalers, for example, a TUE is valid for 4 years,
If it seems like the number of TUEs are low, perhaps it's because it is what it seems to be. The point of the study is to show with objective data, that TUEs are not all that common, and it is not the performance enhancing doping loophole that so many seem to believe it is. Part of what might fuel that belief is another mistaken belief that certain inhalers, as well as other medicines like thyroid medication require a TUE.
If WADA guidelines are respected, TUEs are not likely to be performance enhancing beyond restoring what would be a normal level of performance, as that is one of the explicit criteria to grant a TUE. In other words, if it could be performance enhancing, the TUE would not meet the criteria to be granted.