My approach:
1. Residential consumption:
# People > People/household > Avg. monthly Household consumption > % purchased through online
2. Commercial consumption:
On average people eat out twice every week > 2/7 * (Monthly Residential Online Grocery consumption)
3. Total consumption/market size: Residential + Commerical
I have the following doubts -
1. Is there another approach for this problem, example from the supply side
2. For residential consumption, how to come up with average monthly household consumption