Guestimating how many radical Islamists there are out there in the world

Barack Obama claims that 99.9% of Muslims don't agree with the religious interpretations that force Muslims into violence. With an estimated 1.6 billion Muslims in the world, that 0.1% who are radical still comes to a lot.

But Aaron Goldstein remembers that Daniel Pipes estimated that 10% to 15% of Muslims subscribe to radical Islam. Putting the calculator to work using the lower 10% number, he finds that the number of radicals is around 160 million. That's rather a lot. No wonder Obama wants to downplay that number. And no wonder Obama seems to be unable to address the problem.