Yes, assuming you can find all the old chart toppers (and that this term has a consistent meaning over the whole time interval you're looking at). If, understan

Yes, assuming you can find all the old chart toppers (and that this term has a consistent meaning over the whole time interval you're looking at). If, understandably, you have some gaps in old chart toppers, you need to assume something about them (probably that they were worse than all surviving ones, which helps if you're doing percentile-based comparisons).