Uncoated paper and paperboard, of a kind used for writing, printing or other graphic purposes, and non-perforated punch-cards and punch tape paper, in square or rectangular sheets with one side <= 435 mm and the other side <= 297 mm in the unfolded state, of which > 10 % by weight of the total fibre content consists of fibres obtained by a mechanical or chemi-mechanical process, n.e.s. 5 5 5 4 4 4