(a) Public security years are computed for each separate public security that is part of an issue or series of public securities by dividing the principal amount at par value of the public security by 100 and multiplying the resulting quotient by:
(1) the number of years from the date interest begins to accrue on the public security to the date the security is scheduled to mature; or
(2) for a floating rate public security, the number of years from the date net interest cost begins to accrue on the public security to the earlier of:
(A) the date the security is scheduled to mature; or
(B) any date interest on the security is computed.
(b) If any portion of an issue or series of public securities is subject to a mandatory redemption before the scheduled maturity that at the time of delivery of the public securities is scheduled to occur on a specific date or dates, the public security years are computed as if the face amount of public securities required to be redeemed on each earlier date were scheduled to mature on that earlier date.