The basic benefit for a member who has met the eligibility requirements for normal retirement is a monthly pension equal to 2% of the member's average monthly compensation, multiplied by the number of years of service completed by the member, up to a maximum of 25 years of service. Such monthly pension shall be payable for the life of the member with payments continuing after the member's death to the member's spouse equal to 50% of the amount payable to the member on the day of his death. Such member must have been married to the spouse for at least one year prior to the date of the member's death in order for the payments to continue to the spouse.