I wasn’t sure about this figure (and may have got the age range a bit mixed up, possibly was 0-11 years) but I’ve seen this sort of figure quoted a few times – mostly by the “liberal” journos who write for the Grauniad/Auntie etc

I suspect its all those bling prams with proper pneumatic tyres on them and nannies/pre-school fees, doing up the house for the “baby’s room” and looking at London prices for everything..