Apple has yet to provide any guidance on 5C sales, of course, but The Register’s own, loosely scientific measure - “how often do you spot a given device on the London Underground” - has shown a marked increased in 5C sightings over the past week or so.
The underground is about the last place I'd bring out my phone. Far too many inquisitive eyes and sticky fingers for my liking.
As a formal 'El Reg Unit of Measurement' IMHO it leaves a lot to be desired. There are better ones like
'Walking along Oxford St at Lunchtime' At least you can get a signal there so the fandroids can't snark back, 'you are holding it wrong' now can they? (they probably will but don't they realise it is long past it's sell by date as a joke?)
And no, I don't own even a modestly desirable portable speaking device. Mine is strictly out of the steampunk era I'm afraid.