It is per capita:
Gravy Analytics used location intelligence to compare consumer attendances at ice cream venues nationwide, from January 2017 to March 2018. They then compared population number to determine which states eat the most ice cream for their size.
Agreed. What makes it particularly odd is their command description:
First off, because random ice cream consumption figures doesn’t seem particularly relevant to their main mission. And secondly, because they’re supposedly experts in data analysis but they suck at it.