Periodic : Occurring or recurring at regular intervals, as determined by the individual organization (e. g. , weekly, monthly, quarterly, semiannually, yearly)
NFPA 1401 Recommended Practice for Fire Service Training Reports and Records, 2001 ed. http://www.nfpa.org/assets/files/AboutTheCodes/140 1/1401-F2005-ROP.pdf, (Recmm Prac: Fr Srvc Trng Reports and Records - Amer) {393 NFC}