It is a condition in awarding of the subsidy that the contractor agrees to make a report under oath, in form and manner designated by the Department of Transportation and Public Facilities at the end of each year, giving the following information: (1) tariff sheet of freight rates for the route covered;
(2) total tonnage carried;
(3) gross earning from freight and mail service rendered, segregating the two amounts;
(4) a statement in detail of all expenses incurred and on what account, the names and addresses of all persons employed, and the gross earnings and gross expense of the route covered.