Polyethylene (abbreviated PE) or polyethene (IUPAC name polyethene or poly(methylene)) is the most common plastic. The annual global production is approximately 80 million tonnes. Its primary use is in packaging (plastic bag, plastic films, geomembranes, containers including bottles, etc.). Many kinds of polyethylene are known, with most having the chemical formula (C2H4)n. Thus PE is usually a mixture of similar organic compounds that differ in terms of the value of n.