Commencing as early as practicable in the year 1971, and every ten years thereafter, Council shall determine by census the resident population of each ward, and shall apportion them equally, and, if necessary, shall redefine the boundaries thereof, so that there is no disparity, in resident population, of more than 10% between wards; provided, however, that this shall in no way limit, nor preclude, an increase in the number of wards, and further provided that each ward shall be comprised of compact and contiguous territory. (Added 5-5-70.)