The board of county park commissioners, serving as the special assessment commission, shall make or cause to be made a complete list of the annual benefits and assessments setting forth each lot or tract of land assessed, the amount each lot or tract is annually benefited by the service, and the amount annually assessed against each. There shall be attached to the list of assessments a certificate signed by a majority of the members of the special assessment commission certifying that the same is a true and correct assessment of the property therein described to the best of their judgment, and stating the several items of expense included in the assessment.