Consumption data (at least in the US) is tracked by two major vendors: Nielsen and IRI. They have all PoS data as it relates to you, and sell that data for $.

Consumption data (at least in the US) is tracked by two major vendors: Nielsen and IRI. They have all PoS data as it relates to you, and sell that data for $. The store, distributors, and cpg companies themselves all might buy this data. Usually they sell it aggregated for reporting purposes but that's not to say they can't break it down to get to your granularity.