Except as otherwise provided in this subsection, for each period in which an employee continues life insurance after retirement or while in receipt of compensation under subchapter I of chapter 81 of this title because of disease or injury to the employee, as provided under
section 8706(b) of this title, a sum equal to one-half of the amount which is withheld from the employee’s annuity or compensation under
section 8707 of this title shall be contributed by the Office from annual appropriations which are authorized to be made for that purpose and which may be made available until expended.