Overall, more people in the United States favored the whole milk and were consuming it more than the low-fat milk in 1970. In 1990 both whole milk and low-fat milk were being consumed the same with around 14 gallons per person. At the end the low-fat milk became more popular than the whole milk.
The whole milk had its peak with 25 gallons per capita at the beginning of the period, kept falling throughout the period, just below 15 gallons in 1990, and at 5 gallons in 2015.
Meanwhile, the low-fat milk started low around 6 gallons in 1970, then increased until it caught up with the whole milk in 1990 at just below 15 gallons, and maintained stable till 2010 before falling slightly to around 13 gallons at the end of the period.