How many Jehovah's Witnesses are shunned (DF'd) or fade or disassociate each year? I have heard numbers as high as 50,000.?

That would be hard to determine, they don't share such info and even claim they don't shun.

I'd like to know the answer.

Actually, we do disfellowship unrepentant evildoers. The numbers are not important, but the point is that if one of Jehovah's Witnesses comes to a person's door, this is one of many safeguards that we have to prevent wrongdoers from claiming to be Christians and taking on Jesus' commission while not living it themselves. In this way, we make the effort to prevent this from happening:

(Romans 2:21, 22) . . .do you, however, the one teaching someone else, not teach yourself? You, the one preaching, “Do not steal,” do you steal? 22 You, the one saying, “Do not commit adultery,” do you commit adultery? . . .

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I don't know, but there were 275,581 that became Witnesses in 2014.