The US used 16 fl oz to the pint, hence the pint/quart /gallon being .83 of the size of the UK equivalents.
 
	 
 
	The one thing with Imperial is that it evolved to fit humans- some measurements like rainfall end up with double or even triple figures,
 
	difficult to envisage, when using millimetres, whereas "Bloody hell, we had 3 inches of rain yesterday" makes sense, especially when the exact amount is not important.
 
	'75mm' means '75mm', whereas '3 inches' can often mean an amount that just looks about right, but may be actually 2 3/4" or 3 3/8", but who cares?
 
	'75mm' is what a person running a weather station would say, but '3 inches' simply means it pissed it down.
 
	 
 
	You have to look beyond the figures, and how the units relate to people.....:-)