That's an interesting question. I don't think anyone could answer that accurately because there are too many variables. Suffice to say, the smart aleck answer, in this case, would be the best answer...."as much as it needs".
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There's no certain answer to your question -- there are so many variables!! Weight, height, sex, age -- they all play a role in it. The short, skinny, young female may only produce a fraction of what the tall, over-weight older male may produce.