As the milk protests rumble on, new data has revealed that the price of milk has fallen 16% over the past three years, compared to an average 11% hike in other grocery categories.

The price of milk has fallen from 69.5ppl in 2009 to just over 60ppl this year, according to data analysis by SymphonyIRI. There was an 11% average price increase across the other packaged grocery categories tracked by the company.

Though levels of promotion have not been as high recently as those in other grocery categories, “a continuous level of price reduction is having a similar effect, keeping prices artificially low for shoppers,” said Tim Eales, strategic insight director.

Milk provided retailers with the highest sales returns of all packaged grocery products by value, he added.

Milk generated £3bn in sales value in 2009, but that had dropped to £2.7bn by last year.