What is the relation between production, meals and total export price?

I'm playing Tropico 4 right now, but I'm pretty sure it's the same for all Tropico games. I've finished the normal campain, but I'm still wondering what these numbers are about.

So let's take an example :

• In the "Trade" tab, I can see the "price" of fish (1 ton ? 1 fish ? 1 unit ? something else ?) is : 576 $

• Now I click on my fish farm and I can see the total export so far is : 5372 $

• The total amount of production (units ? fishes ? tons ? ...?) is 1317

• The amount of meal is 0

• The "Stock prod." is 100

So how are these numbers related ? I would expect that "total export" / "amount of production" = 5372 / 1317 = 4.08 $ would give me a number around the price of a unit, but no, not at all.

Here is a screen cap (french version) :

Same question for a random farm (Maïs probably means "Corn"), and the price in "Trade" tab is 960 :

"Exports" is the cash value of product that has been exported. Food products that are eaten (directly from the production building or through a Marketplace) don't count. Products that are turned into something else (e.g. canned fish) don't count. Products that are slated for export but not actually exported yet - being moved around, sitting on the dock waiting for a ship - don't count.

"Production" is the total that's been produced at that building, regardless of what happened to it.

"Meals provided" is the number of times a person has gotten food from the building.

"Output storage" is the amount currently sitting in the building, waiting to be hauled somewhere (or eaten).

Also, note that export prices can change over time: from random or scenario-specific events, the effects of your Economic Minister and edicts, the Customs Office, etc. This can lead to a total export amount that's different from what those resources would be worth if exported right now.