669 - Metallurgy 521
660 - Chemical engineering 361
665 - Industrial oils, fats, waxes & gases 245
668 - Technology of other organic products 124
662 - Explosives, fuels & related products 64
666 - Ceramic & allied technologies 62
664 - Food technology 54
661 - Industrial chemicals 39
667 - Cleaning, color & coating technologies 28
663 - Beverage technology 16