March 4 (SeeNews) - The Zagreb Stock Exchange said on Friday it will add plastic goods producer AD Plastik [ZSE:ADPL-R-A], lender Privredna Banka Zagreb [ZSE:PBZ-R-A] and food producer Belje [ZSE:BLJE-R-A] to its 25-share benchmark CROBEX index as of March 21.