In how many markets?
The thing about international numbers it seems is that studios love to pimp them pre domestic release to build up momentum(who wouldn't want to see a movie that's doing well). The reality being that, though always impressive no doubt, these numbers are always never presented in a controlled manner. It's always, records after record being broken but the last film opened up in 4 theaters in korea and the new one in 4 more countries...
Not to take anything away from the sheer tickets sold, but I personally almost never look at international debut's in a comparative sense. Asia has turned into such a huge market these days, and some films open there whilst others do so months later...just seems like there is no sense of relativity. Not like a domestic opening(though that has it's own issues).
That being said, it looks like Ironman has a good shot at a billion. Unless it looses steam(as Iron man has in the past runs). Another strong start to the Summer for Marvel. I wonder if some studio has the gull to take this early may spot next year.