(I'm a bit surprised that you got 30k visitors - that's more than I would have expected at that hour.)
That time of day suggests the American demographics are undercounted (not just US but Canada etc. too). On the other hand, your numbers are close to what I found when I did a similar analysis (already 5 years ago):
...Although Brits tend to be familiar with "plurality" in my experience, while Americans tend to have no clue what a relative majority is (judging by the downvotes of the GP, it looks to be holding true).