What is the average household income in cities in the state of New Hampshire where there are stores of the type city?
"New Hampshire" is the State; average household income = AVG(Household Income)
SELECT AVG(T2.`Household Income`) FROM Regions AS T1 INNER JOIN `Store Locations` AS T2 ON T2.StateCode = T1.StateCode WHERE T2.State = 'New Hampshire' AND T2.Type = 'City'