PETN or, in other words, Pentaerythritol tetranitrate, is a vital ingredient of the (in)-famous explosive Semtex. It was also the chief ingredient of the explosive charge used, thankfully without success, by the latest airplane bomber-to-be, Farouk Abdul Mutallab.
It is believed Farouk Abdul Mutallab had moulded a quantity of the explosive powder to his body, sewn into his underwear in a six inch packet. He then attempted to detonate the device using a syringe containing a liquid, which was later recovered on the aircraft by FBI agents. Officials believe tragedy was only averted because the makeshift detonator failed to work properly.For curiosity sake, I have checked on Google Trends how the interest in PETN behaves, geographically speaking, and the result was somewhat surprising (click to enlarge):
It shows that Iran produces at least twice as much PETN-related traffic as the second to fourth contenders (India, Germany, Israel, Australia, Finland, USA). Taken in conjunction with the second ("Cities") and third ("Languages") columns of this survey, the result for a layman statistician like me pointed to somewhat grotesque picture of a rural Iranian proficient either in German or Finnish researching the uses of PETN...
It might be of interest that small (population-wise) countries like Israel and Finland generate significant traffic too, but then Google lumps Israelis and Palestinians in one statistical lump. Finns - who knows, perhaps they need high explosives to deal with tree stumps or summat.
You explain Switzerland, I get tired quickly.