(1) The department shall compute and levy a tax upon the property of each company defined in s. 76.02, as assessed in the manner specified in ss. 76.07 and 76.08, at the average net rate of taxation determined under s. 76.126. The amount of tax to be paid by each such company shall be extended upon a tax roll opposite the description of the property of the respective companies. The tax rolls for all companies required to be assessed on September 15 in each year under s. 76.07 (1) shall be completed on or before October 1; and the department shall thereupon attach to each such roll a certificate signed by the secretary of revenue, which shall be as follows: "I hereby certify that the foregoing tax roll includes the property of all railroad companies, air carrier companies, conservation and regulation companies or pipeline companies, as the case may be, defined in s. 76.02, liable to taxation in this state; that the valuation of the property of each company as set down in said tax roll is the full market value thereof as assessed by the department of revenue, except as changed by court judgment, and that the taxes thereon charged in said tax roll have been assessed and levied at the average net rate of taxation in this state, as required by law".