My point being that artists like Diana Krall can sell a lot of albums - way more than the latest Dave Holland or Charles Lloyd album. When a big-selling album by a vocalist gets the "jazz" tag, even if it's not, really, it can distort the overall `numbers somewhat.
My point wasn't that jazz fans really like jazz vocals - like you, I'd be surprised if that was the case. However, when crossover type albums with vocals get categorized as jazz for charts purposes, it can affect the overall numbers.
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