How many words roughly in the Japanese language?

Because I'm quite sure that the average vocabulary of an English speaker is 5000 words - that is not even the number of words needed for the JLPT2 let alone the JLPT 1 which is 10,000 words.

Answers are all apreciated :)
Update: By how many words I am asking more along the lines of how many in common use...
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