Every person who is receiving an annuity computed pursuant to the retirement law in existence prior to July 1, 1970, or who is receiving a special pension (regardless of when granted), is hereby granted a cost-of-living increase of ten percent (10%) in the amount of his annuity or pension; Provided, That no pension increase shall be granted to a person who is also receiving a retirement annuity, but said annuity shall be increased if it qualified for same hereunder.