That number came from a report from Grey, Clark, Shih and Associates, Ltd in 2018.

The study, which focuses on changes introduced by the 2014 Farm Bill, shows that in 2015, the American government doled out approximately $22.2 billion dollars in direct and indirect subsidies to the U.S dairy sector. The report estimates that in 2015, the support granted to U.S dairy producers represented approximately C$35.02/hectolitre – the equivalent of 73% of the farmers’ marketplace revenue.  USDA data also reveals that US dairy farmers operate at a loss, and have a cost of production that is higher than what they earn from the marketplace