1. The costs of special personal service, financial advisers, special consultants, and office supplies and equipment shall be borne by the board of trustees.

2. Annually the board of trustees shall estimate the amount of money necessary to provide for the expense of the administration and operation of the retirement system for the ensuing year, excluding those items the cost of which the board is to bear pursuant to subsection 1. Fifty percent of the estimate shall be provided by the city and the remaining fifty percent shall be provided by the board of trustees from interest and other earnings on assets.

3. Annually, the board of trustees shall estimate the amount of money necessary to be paid into a board of trustees account during the ensuing year to provide for the expenses of the retirement system for the cost of special personal service, financial advisers, special consultants, and office supplies and equipment.