Найдите подлежащее в предложении по британскому языку. Only 40 per cent

Only 40 per cent of the last years supply of potatoes reached the storages. Только 40 процентов прошлогодних припасов картофеля поступило на склад.

Reached is the predicate of this sentence. This sentence is in Past Indefinite. Past Indefinite is formed with the help of the suffix ed or we use the second form of irregular verbs. The auxiliary verb of Past Indefinite is to do. We use the second form did.

 Negative.

Only 40 per cent of the last years supply of potatoes didnt reach the storages.

Interrogative.

Did only 40 per cent of the last years supply of potatoes reach the storages?