“Parent’s annuity” shall be provided for the natural parent or parents of a fireman who dies on or after the effective date while in active service, or is disabled and in receipt of or pending receipt of disability benefit, or upon leave of absence with whole or part pay, or upon leave of absence without pay during a period of not more than 3 months in the aggregate, or in receipt of annuity granted after 20 years of service, or while out of the service after 20 years of service and pending receipt of annuity to which the fireman has a right upon attainment of age 50 or more; provided, that at the time of the fireman’s death, no widow or unmarried child under 18 years of age entitled to annuity survives him; and, provided further, that satisfactory proof shall be made to the board that the fireman was contributing to the support of his parent or parents.
     Parent’s annuity shall be 18% of the current annual salary attached to the classified position held by the fireman at the time of his death or retirement and each surviving parent shall be entitled to receive said 18% annuity on a monthly basis.