Wash. Rev. Code § 81.24.020
On or before the date specified by the commission for filing annual reports under RCW 81.04.080, every auto transportation company must file with the commission a statement showing its gross operating revenue from intrastate operations for the preceding year and pay to the commission a fee of two-fifths of one percent of the amount of gross operating revenue. The commission may, by rule, set minimum fees that do not exceed the cost of collecting the fees. The commission may by rule waive any or all of the minimum fee established pursuant to this section.
The percentage rate of gross operating revenue to be paid in any period may be decreased by the commission by general order entered before the fifteenth day of the month preceding the month in which the fee is due.
RCW 81.24.020