Organic foods now occupy prominent shelf space in the produce and dairy aisles of most mainstream U.S. food retailers. The marketing boom has pushed retail sales of organic foods up to $21.1 billion in 2008 from $3.6 billion in 1997. U.S. organic-industry growth is evident in an expanding number of retailers selling a wider variety of foods, the development of private-label product lines by many supermarkets, and the widespread introduction of new products. A broader range of consumers has been buying more varieties of organic food. Organic handlers, who purchase products from farmers and often supply them to retailers, sell more organic products to conventional retailers and club stores than ever before. Only one segment has not kept pace-organic farms have struggled at times to produce sufficient supply to keep up with the rapid growth in demand, leading to periodic shortages of organic products.