In the century between 1915 and 2015, the price of milk went from 17.6 cents for a half gallon to $3.50 for a full gallon. The highest price of the decade as of December 2015 was $3.90 in November 2007.
Since the beginning of the 20th century, the five-year average price of milk has risen consistently. Not a single half-decade has elapsed that did not show a significant increase in the price per gallon of milk. This is remarkable, as not all other food commodities have behaved in the same manner. For instance, many meats have risen in price, only to regress as much as 30 years.
Over the past 10 years, the price of milk has been relatively stable. The lowest price since January 2005 was less than a dollar below the ten-year high at $2.98. Apart from these few peaks and valleys in the average price, a gallon of milk has remained in the mid-$3 range somewhat consistently.
In some states, such as California, the price of milk is government-regulated. As with any other industry, the cost of dairy production is directly affected by labor and overhead costs, but has industry-specific costs such as veterinary care and packaging costs.