Economics joke of the day

A lone sailor finds himself shipwrecked on a small island. Fortunately he's not alone, as he finds a small community. The sailor comes across a butcher on the street selling some rather unusual produce. The butcher has in stock human brains, collected together according to the source. The sailor reads the sign:

Laborer: $9/lb
Artisan: $14/lb
Scientist: $21/lb
Politician: $39/lb

The sailor exclaims, "Wow, I guess politicians must be really smart and popular!"
To this the butcher grumbles, "You must be kidding. Do you have any idea how many politicians I gotta kill for a pound of brains?"

HT: a former student (J.S.)