How Many Words Did Shakespeare Know?

Last century, many English linguists was proud of that English had more words than German and French. It is prove of that English was better than other language. But on the other hand, rarely some English linguists wanted to study how many English words, an English speaker could master. Only occasionally some paper revealed few data and the number was various from 250,000 to 150,000, from 70,000 to 30,000, from 10,000 to 20,000, anyway, no one could be trusted. Even the words number of Shakespeare was questionable. 

When I search ‘How many words did Shakespeare know’ from Google, I find a page:

http://www.jstor.org/discover/10.2307/2335721?uid=3737536&uid=2&uid=4&sid=21103185003707 it says that by a special calculation Shakespeare knew 31,534+35,000=66,534 words, compare a normal English speaker only master 10,000 to 20,000 words.

William Shakespeare (26 April 1564– 23 April 1616), yet when I check other documents, I find that the development of English dictionary is:

1658 ‘The New World of Words’ Edward Phillips, it had 17,000 words. (Shakespeare died 42 years)

1702 ‘A New English Dictionary’ by John Kerseyit had 28,000 words

1708 ‘Dictionarium Anglo－Britannicun’  by John Kersey it had 35,000 words

1730  ‘Dictionarium Britannicum’ by Nathan Baileyit had 48,000 words

1736 second edition of ‘Dictionarium Britannicum’ by Nathan Baileyit it had 60,000 words

The contradiction is that at Shakespeare’s time where were the 66,534 words? If Shakespeare really knew 66,534 words, the editor of the later dictionary didn’t need looking for other book, just collect Shakespeare’s work would find what the Nathan Baileyit found on 1736 that was 120 years after Shakespeare died.