"IF the other 64% had registered and voted (either directly or by proxy), that would be 3.68 million more votes."

That would be to assume that 100% of those in that age group who were eligible to vote would have done so, would it not?

If so, then your final figure would be a bit too high. How about re-doing the calculation using 75%, or whatever the turnout of the remainder (not the population as a whole because that figure was skewed by the low % of 18-24s) of the poulation was?

But your argument is a strong one nevertheless, and does highlight the difficulty of making democracy work.

But going off on a bit of a tangent for now, was it sufficient to just ask yes or no, in or out? It is now becoming apparent that the question was too simple. An opportunity was missed to find out what the public will is concerning whether the negotiations should be about leaving the single market or staying in, and whether we are OK with free movement for EU citizens or not?