It shall be the duty of the city clerk of the city of Aberdeen to keep an appropriate account with each office, department and subject covered by the annual budget adopted by the council, in which account there shall be credited to each office, department, and subject the amount allowed thereto for the current year's expense as shown in the adopted budget, to be itemized so far as necessary for a proper understanding of the same. As fast as the expenditures are made and warrants issued, the city clerk shall make proper segregations and shall charge up in such account against each office, department and subject the expenditures properly chargeable thereto. He shall take off a monthly trial balance from such books of account and submit the same to the council once a month. When the amount allowed in the adopted budget for any office, department or subject is exhausted, the city clerk shall notify the council of that fact.