A long time ago...
I got curious about how much caffeine there is in RC Cola as manufactured in Canada, so I called up Cott Beverages and asked. A 355 millilitre can of RC Cola has 43 milligrams of caffeine, or a little less than Coca-Cola, according to the FAQ I found. The same FAQ lists RC Cola as having 36 milligrams per can, so perhaps it has changed, or is higher in Canada.
I got curious about why Mountain Dew has no caffeine in Canada. (If you don't believe me, get a can and check it for yourself.) and called the 1-800 number on the can. The telephone operator on the other end said that Dew is the wrong colour to be caffeinated in Canada. Apparently a drink has to be brown so that people know what to expect. Now, as far as I know, coffee and tea (which also has caffeine in it) are both brown only by coincidence, since it's the tannin in tea which makes it brown, and (also as far as I know) there's not much tannin in coffee. If Coca-Cola didn't have caramel in it to make it brown, who knows what the rules might be..