You are the PM for a superstore chain. One store has been loosing profit YOY. What metrics would you request to help you investigate?

The first 3 years the store's profits were increasing YOY. The last 2 years the store's profits have been degressing. 

Clarifying questions : 

Is there any huge decrease in profits in a month?

Profit = Margin * Items Sold

So what has decreased? Considering profits of other stores has not decreased probably margins have not changed, items sold is decreased.

Do we have system to place and Deliver home deliveries? Is there any decrease in it?

Is there a specific decrease in sale a category of products? 

Is there a decrease in distribution / availability of a product in the area which has demand there?

Transaction issues: Are we able to do transactions in the store same as before? Network ,  Technology there is fine? 

If there is no decrease specifically in a category or product.

External Factors : Has there been any new store opened 2 years ago which may have affected the sales. 

Is the distribution cost same as before? Any Real estate changes which happened in the location?  

Internal Factors : Is the store inventory cost and numbers same as before? Have we increased the expenditures Rent costs, Salaries in the store? 

Any decrease in number of yearly orders, monthly orders placed, daily orders? User flow : If we have no decrease in daily customers coming to the store but have decrease in number of orders placed. Are the store interior, settings changed. Shelf placements affected? 

These are some questions to perform the drill according to me, please share your reviews.