Why on earth would you think I was referring to election results?
Erm, because upthread you expressly referenced 'voting', something usually associated with elections or referendums. Either way, election or referendum, the results are always presented as % of turnout, not total population.
You can express support for x or y issue as % of the total population to put it in context. Capital punishment for example.
Express support how? Are we talking surveys/polls?? Any survey that seeks to work out support for an issue will present its data as a % of those who participated in the survey.
Good surveys will capture a wide demographic and a large nationwide sample size, in which case some projection (with a margin of error) of opinion can be made on the wider populace. However, we have seen recently how wide of the mark surveys and polling can be.
If you want to chop off the 20 million under 18s - the Brexit vote is still only 35% of the adult population. A fraction.
It's not 'chopping off', they are under current legislation not allowed to vote. Not sure why you insist on trying to include teenagers and toddlers in the democratic process.
Crucially, the UK voted to leave the EU by 52% to 48%, based on those who got off their arses and voted. Personally, I wish the threshold was higher to enable a stronger mandate, but it wasn't. Unfortunately out of those who voted, fewer people opted for remain, so even if we use your dubious methods the remain vote would be even less then 25%. You can lament the fact that millions of people eligible to vote did not bother to, but you can't start lumping those people and under 18s in as 'remain' just to bolster your numbers.
Your "agenda" & "tactics" conspiracy - is tedious.
Pointing out your cynical use of statistics that seeks to cast doubt or delegitimise a democratic outcome that you disagree with is not a 'conspiracy'.