(1) Subject to this section, every inmate serving a sentence of more than 12 months is eligible for parole after having served a period of 1/3 of such sentence or 12 months, whichever is the greater.
(2) Where concurrent sentences have been imposed on an inmate, the inmate is eligible for parole in respect of the longest of such sentences, after having served 1/3 of the period of that sentence or 12 months, whichever is the greater.
(3) Where consecutive sentences have been imposed on an inmate, the inmate is eligible for parole after having served 1/3 of the aggregate of such sentences or 12 months, which ever is the greater.
(4) Subject to subsection (5), an inmate who has been sentenced to imprisonment for life or, in respect of whom a sentence of death has been commuted to imprisonment for life, is eligible for parole after having served a period of not less than 15 years.
(5) At the end of every period of 15 years, the Board shall review the cases of all such inmates as are referred to in subsection (4) for the purpose of deciding whether or not to grant any of them parole.