368.109 Regulatory assessment fees.—Each natural gas transmission company operating under ss. 368.101-368.112, for all or any part of the preceding 6-month period, shall pay to the commission, within 30 days following the end of each 6-month period, a fee that may not exceed 0.25 percent annually of its gross operating revenues derived from intrastate business excluding sales for resales to natural gas transmission companies, public utilities that supply gas, municipal gas utilities, and gas districts. The fee shall, to the extent practicable, be related to the cost of regulating such natural gas transmission companies.