I just checked my yogurt. It’s milk yogurt from outdoor cows that are actually in a meadow, not in a stable. The yogurt is made from whole milk, so not from skimmed milk.
My yogurt contains 35 grams of sugar per litre. That sounds like a lot, but no sugar is added; it’s the natural lactose from the milk, or what’s left of that lactose after the yogurt bacteria have processed most of it.
I estimate that I consume about one litre of this yogurt a week.