Dear Henry, Thank you for visiting the KOSIS website. According to the change in the base year into 2015, the sub-categories of "Copper" were partially changed. The names of two sub-categories were changed, and "Copper plate an strip" was excluded from data dissemination. In summary, 1. Copper bar and section -> Copper bars: Changed the name of category (The same coverage) 2. Copper wire -> Copper wire bar: Changed the name of category (The same coverage) 3. Copper plate and strip: Excluded from data dissemination 4. Copper tube -> Copper tube: No change In part, the exclusion of "Copper plate and strip" attributes to the small number of establishments. (In that case, the characteristics of a specific establishment may be disclosed.) In the meantime, please pay careful attention to the use of time series dataset (201501~201712 in the past dissemination) because new establishments are included or some previous establishments are excluded from statistical production when revising the base year. Thank you.