The report also notes that volume gains will lag value gains as the average weight per container unit continues to fall, reflecting preferences for small, single-serving containers in a number of food and beverage markets, and lightweighting of containers to reduce material use and enhance sustainability. Also, despite increased competition from pouches and other types of flexible packaging, these will often augment rather than replace rigid containers. PET and high density polyethylene (HDPE) are by far the primary plastic container resins, accounting for a combined 86% of demand in 2011.
 

Bottles and jars, which represented 77% of plastic container poundage in 2011, are by far the leading plastic container type. Through 2016, plastic bottle and jar demand is expected to rise 2.8% per year to 165 billion units, moderated by the already-dominant position of plastic in many applications, with few new areas existing for large-scale conversions. Additionally, bottle unit growth during 2001-2006 benefited greatly from booming sales of bottled water. Moving forward, a considerable decline in bottled water growth is expected based on environmental factors. However, developments will be aided by healthy prospects for smaller single-serving beverage bottles. Among major bottle and jar markets, the fastest gains are predicted for pharmaceutical and food applications. 

Faster volume gains are expected for other plastic container categories, such as tubs, cups and bowls. Demand will be backed by popular trends like convenience, portability and portion control benefits of single-serving cup packaging as well as favorable outlooks for certain foods (e.g., yogurt, hummus, single-cup coffee) typically packaged in tubs and cups. A rebound is expected for plastic pails based on a recovery in construction activity from low levels in 2011, which will increase demand for paints, adhesives, driveway sealers and other goods typically packaged in pails.