Well, I don't know about unique passengers per year, but ATL alone serves a total of 80 million + pax per year. I think worldwide, I've seen the number 2.2 billion passengers per year before, but I can't remember where. That's obviously nowhere near the unique number, but someone on FT has got to have a solid estimate from somewhere.

As for the second number, you can try searching for the average total number of suicide attacks worldwide per year. By their very nature they're unique. I think the conservative number would be to assume that everyone who has the resolve, mindset, nad motive to be suicide attacker probably is in an environment with the opportunity to do so since its that same environment leads them to arrive at that extreme one way or another.

IMO, an easier calculation would be total number of airline flights per year vs total number of terrorist attacks worldwide per year (hot war-related attacks excepted).

peace,
~Ben~