By failing to account for obvious and known confounds, the graph is rendered significantly less meaningful. By way of analogy, one could look at rainfall avera

By failing to account for obvious and known confounds, the graph is rendered significantly less meaningful. By way of analogy, one could look at rainfall averages over the whole of the US and conclude that some place is/is not in a drought. You could do this by ignoring the obvious confound that different places get different amounts of rainfall. For some places, it would be true. For others, not.