Wal-Mart has announced a "dramatic" increase in the number of US consumers buying "green" products.

Research carried out by the US retailer claimed that consumers were buying 66% more "green" products than last year.

Wal-Mart claims the growth seen in its "Live Better Index" shows concern for the environment has a growing presence in shopping baskets.

"The fact that product adoption has increased dramatically in one year shows that the decisions our customers make in the aisles, coupled with Wal- Mart's commitment to providing more eco-friendly choices at the best value, is helping consumers and the planet live better together," said Stephen Quinn, chief marketing officer at Wal- Mart.

The index said US consumers were buying more organic milk, with organic sales accounting for 1.58% of all milk sales at Wal-Mart, compared to 1.15% last year.

Consumers, however, are buying less organic baby food and formula, with organics accounting for 4.12% of sales, down from 4.31% in 2007.