Each person who becomes a member of the retirement system under the provisions of this article shall contribute each month to the retirement system, commencing on the effective date hereof, four percent if he or she be a safety member, otherwise three and one-half percent of his or her gross salary before deduction for any reason other than absence from duty, to be applied on the cost of the benefits at death or retirement provided for him or her under this article. Should any person who is a member under the provisions of this article be separated from city service through any cause other than death or retirement, then all of his or her contributions with interest, shall be refunded to him or her. (Prior code § 34.02.207)