Okla. Admin. Code § 165:5-3-25
(a) On or before April 1 of each year, each affected public utility shall submit to the Director a report based on the preceding calendar year containing the following data:
Added at 10 Ok Reg 4517, eff 9-1-93 (emergency)
Added at 11 Ok Reg 3681, eff 7-11-94
Amended at 30 Ok Reg 1033, eff 7-1-13
Amended at 31 Ok Reg 959, eff 9-12-14