Even what is called "1 standard drink" isn't standardised across countries though.

For you, and also us in NZ it's 10g of ethanol (approximately 12ml), in the UK it's 8g. The US does in fact have a standard measure too, but 14g (and I don't know enough to know how widely it's actually used).

So as well as the standard drinks per bottle, the rule-of-thumb has to differ between countries too.