An increasing proportion on trade has been with other European Community member countries.
Has an increasing proportion on trade been with other European Community member countries? - общий вопрос. вспомогательный глагол выходит на первое место
With whom has been an increasing proportion on trade? - специальный вопрос, вопросительное слово на первом месте
Has an increasing or discreasing proportion on trade been with other European Community member countries? - альтернативный вопрос, вспомогательный глагол на первом месте
An increasing proportion on trade has been with other European Community member countries, hasn't it? - разделительный вопрос