Not so bad for a machine, I once met a French Telco guy in charge of buying/selling minutes at a large operator who thought that "billion" meant "two million"
The fact that international confusion over billions doesn't arise more often points out how bad people are at thinking about large numbers. We mostly don't notice the difference between a billion and a trillion.
Same in Norway. I'm from the US and the large numbers always take some thought. I didn't realize that I'd have to relearn counting when moving here, but honestly it is easier than trying to relate the time of day.
i remember reading something similar (unit conversion) on HN. Maybe someone can link.