I can't explain it, but I have a couple of qualified guesses:
a) Takata air bags, or more precisely - Takata airbags using the faulty initiators - are disproportionally allocated to the US market for some reason or the other. Perhaps other Takata plants supplying other markets use a slightly different explosive compound than the one being made at Moses Lake?*
b) Perhaps authorities in other countries haven't investigated past crashes and concluded that the airbag caused the fatality, rather than the crash itself, hence they cannot claim that the airbag was to blame for any fatality.
c) Perhaps they do have confirmed fatalities b/c of a Takata airbag, but haven't reported it to whatever authority provided the numbers for the article (yet, anyway).
*) Bingo; found this as I read the article: "He says he hired a propellant specialist to help develop a more stable formula using guanidine nitrate, and since about 2008, Takata in Europe has sold air bags using that. He says Takata’s China team also adopted the formula."
I think tmd83 might be on to something (as well as m_mueller), the NHTSA decided in the ... '70s I think to make the tradeoff to maximally protect those who don't wear belt.
But environmental conditions might also be a factor, the higher the heat and humidity, the faster the ammonium nitrate pellets turn into very dangerous powder. And that's being used to target the limited supply of replacement parts in the US. How does Japan's population distribution and climate compare to the US?
The (very good, worthy of a read) article deals with this. It states that the european subsidiary of Takata developed a propellant based on guanidine nitrate because of concerns with the safety of ammonium nitrate, and have used that since 2008. It also states that their Chinese subsidiary used that one.
Here's my guess: The US and Japan are the largest markets for Japanese cars (I think). Japanese who drive Japanese cars tend to switch to the latest model fairly often, at least more often than Americans. At least I'm seeing way more old cars when visiting the US.
Down the thread in the quora answer there is mention of US airbags deploying at higher pressure to try safeguarding people who aren't wearing seat belts. Could that potentially make the US versions more failure prone and unsafe?
