Recently available 12 consecutive months of actual experience. Not always the most recent 12 months. In a rate proceeding, 12 months of actual operations ending no more than 4 months before the date a rate change application is filed. In reference to the EQUITABLE SHARING MECHANISM, a representative base period must reflect a representative level of purchases by a pipeline's firm customers during a period preceding the onset of changed conditions which resulted in reduced purchases and growth of the take-or-pay problem. See EQUITABLE SHARING MECHANISM, DEFICIENCY PERIOD, PURCHASE DEFICIENCY METHODOLOGY and TEST PERIOD.