The official bonds of the following named officers shall be in amounts as follows: The Manager, $20,000; the Auditor, $5,000; the City Clerk, $5,000; the City Assessor, $5,000; the City Treasurer, $50,000; the City Collector, $10,000.

Provided, however, that the Council may prescribe by ordinance bonds of the City Treasurer and the City Collector in greater amounts than herein prescribed for those officers.