Apple's share of the tablet market collapsed in the third quarter, according to new data from IDC.

IDC says Apple has 50.4 percent of the tablet market, down from 65.5 percent in previous quarter. Samsung, Amazon, Asus, and Lenovo, all took share from Apple during the quarter.

This is a bit of a shock because during Apple's iPad Mini presentation, CEO Tim Cook flashed this chart:

The problem with this chart? There's no source. Tim Cook just threw up on the screen and didn't mention where the numbers come from.

We've been trying to figure out the source, and we think it's from Chitika, which regularly publishes tablet market share data. Chitika is an ad network running on 250,000 sites in the U.S. and Canada. IDC's data is global.

Here's IDC's chart:

If we had to guess, we'd say Apple's true share of the market is somewhere between IDC and Chitika. Net Market Share, which collects data from a network of sites, says iOS has 60 percent of web traffic, compared to Android at 27%. That's a mix of iPhone and iPad traffic, though.

Here's Net Market Share:

And while we're here, why not toss in one more, right? Strategy Analytics thinks Apple has 60% of the tablet market:

So, in conclusion, IDC's shocking data doesn't align with what other people are reporting.

And, more importantly, Apple now has the iPad Mini, iPad 2, and the full-powered iPad. Those should help Apple protect its market share lead this holiday quarter.