It's a far more than 200k people. There's quite a bit of research out there by Pew and other groups that somewhere between 10 - 15% of the global muslim population support what we'd call "terrorism" in the west.

Actually: no such study has been done, a comprehensive one.

The only data that matters is they data like the ones from the CIA world fact book that talks about how many people are actually engaged in Islamic terrorist fighting / organizations

Don't let the facts get in the way of ur ideology though

With attacks on Western Civilian populations, suicide bombings etc. As of circa 2012 there was about another 15 - 20% that would qualify as "sympathetic" to those beliefs.

Yes sympathetic.

Let's say we took a poll of Europeans, none Muslim. And asked them how many felt sympathetic for efforts of the Palestinians.

Would you count that number as also people who are terrorist?

You can Frame questions; poll questions, in a way to get ur desired result

I just remember running the numbers at the time, but there is a population in the muslim world roughly the same size as the US Population (roughly 300 Million People) who either support the use of such tactics or are at least sympathetic to the use of such tactics.

Again: you are misconstruing polls, to what we are actually talking about.

We are talking about people engaged in terrorism

Today I would suspect that number would be a bit less given the rise of ISIS and other such groups and they way they treat...well everybody including other muslims. But none the less it's probably 100 - 200 million people, not 100 - 200k

Engaged in terrorism?

Don't let facts get in way of the down votes...