Each officer, board or commission of any county, city or town, and all employees charged with the management or control, of any department or institution of either thereof shall on or before the first Monday in July of each year, make and file with the board or commission charged with the duty of reporting to the excise board, a report in writing showing, by classes, the earnings and cost of maintaining their respective offices or departments for the previous fiscal year, together with an itemized statement and estimate of the probable need thereof for the current or ensuing fiscal year. Provided, that the report relative to the construction and repair of bridges shall be made by the county commissioners and county surveyors, conjointly, and shall be itemized so as to show the location of each proposed new bridge and the estimated cost thereof, and provided further, that the report relative to the probable needs of the courts of record shall be made by the court clerk and district attorney, conjointly, and shall be itemized so as to show separately the respective needs of each court.