What are the two students talking about?

W: Mmm. This is yummy coffee, Bob. How’s yours?
M: It’s excellent. You know, Teresa, I just read an article about coffee last night. It was in that journal that Professor Clark recommended to us.
W: Which one was that? Oh, I think I know. Food Economics Review. Isn’t that it?
M: That’s the one.  Anyway, in the article there were all kinds of interesting things about coffee that I’d never known before.
W: Yeah? Like what?
M: Well, did you know that over 30 million people earn their living from some aspect of coffee farming?
W: That’s a lot of people. Coffee obviously has a lot of importance economically.
M: Absolutely. In fact, it’s the second most valuable commodity in the world after oil.
W: Wow! Well, if it’s that big, it’s probably produced and controlled by a few large companies, just like with oil.
M: Well, this article said otherwise. It said that most coffee’s grown by farmers with only 4 or 5 hectares of land. And coffee’s usually all they produce.
W: So who produces the most coffee? I mean which country?
M: It depends on what type of coffee bean you’re talking about.
W: Oh, of course. The coffee-growing countries turn out coffee beans with different flavors. My favorite’s Jamaican.
M: Jamaica roughly accounts for 2% of the world’s overall produce.