Actually we're on Prince. And Settlers are not poppable above Warlord difficulty level. (Neither are Workers, incidentally.)
For anyone interested, on Prince difficulty level these are the probabilities for huts (assuming my files are up to date):
Gold: 30% (large amount 10%, small amount 20%)
Barbarians: 20% (few 15%, lots 5%; ignored if the unit is a Scout)
Free Unit: 15% (warrior 10%, scout 5%)
Map: 10%
Experience: 10%
Tech: 10%
Healing: 5% (ignored if unit is at full health)
That means for a Scout at full health, the probabilities are adjusted to:
Gold: 40% (large amount 13.3%, small amount 26.7%)
Free Unit: 20% (warrior 13.3%, scout 6.7%)
Map: 13.3%
Experience: 13.3%
Tech: 13.3%
With 40% odds for gold, that probably explains why so many people have been getting it so much.
Remember this only applies for Prince level. These probabilities vary as the difficulty level changes. Generally the higher it is, the less likely you are to get something really nice (like a tech, a free unit, or gold), and the more likely you are to get barbs. In fact the only two things that remain constant across all the difficulty levels from Settler to Deity are that you always have a 5% chance of getting healed if you're damaged, and you always get a 5% chance of getting a Scout. Everything else changes.