Saffron (trade) by far the world's most important producer: in 2005 it grossed some of dry threads, or 93.7 percent of the year's global total mass; much of the Iranian crop was bound for export. Northeasterly Khorasan Province, which in 2004 was divided in three, grows 95 percent of Iranian saffron: the hinterlands of Birjand, Ghayen, Ferdows in South Khorasan Province, along with areas abutting Gonabad and Torbat-e Heydarieh in Razavi Khorasan Province, are its key cropping areas. During 2004, Iran was not a member of the World Trade Organization. and still until November 2009, Iran was again not a member of
Saffron colouring strength can range from lower than 80 (for all category IV saffron) up to 200 or greater (for category I). The world's finest samples (the selected, most red-maroon, tips of stigmas picked from the finest flowers) receive colouring strengths in excess of 250, making such saffron over three times more powerful than category IV saffron. Market prices for saffron types follow directly from these ISO categories. Sargol and coupé saffron would typically fall into ISO 3632 category I. Pushal and mancha would probably be assigned to category II. On many saffron packaging labels, neither the ISO 3632 category nor