semi-skimmed would be 1% milk = or at least I would guess that would be the equivilant. it is hard to say because...

Most US milk is standardized at 2% milkfat - and is considered "whole" milk by most - though much milk produced in the US is actually between 3.5 and 4 % milkfat when it comes out of the cow...

so the "standard" 2% milkfat sold is already part-skimmed.