Among the customers with a marital status of married-civ-spouse, list the number of inhabitants and age of those who are machine-op-inspct.
OCCUPATION = 'Machine-op-inspct'; number of inhabitants refers to INHABITANTS_K;
SELECT T2.INHABITANTS_K FROM Customers AS T1 INNER JOIN Demog AS T2 ON T1.GEOID = T2.GEOID WHERE T1.OCCUPATION = 'Farming-fishing' AND T1.SEX = 'Male' AND T1.age >= 20 AND T1.age <= 30