More and more consumers are considering the environment before making purchasing choices, according to a new research study announced by Wal-Mart. According to the retail giant, 66 percent more consumers made environmentally-conscious purchasing choices over the previous year. Wal-Mart's metrics are an index of five key eco-friendly products, measured from April to April of each year. The comparison of product sales figures yielded the following results:

Compact fluorescent light (CFL) bulbs. Average adoption rate of 19.7 percent, up from 13.39 percent in 2007. Delaware led the category with an adoption rate of 25.8 percent.

Organic baby food and formula. Average adoption rate of 4.12 percent, down from 4.31 percent in 2007. California continued its lead in the category with an 8.58 percent adoption rate.

Organic milk. Average adoption rate of 1.58 percent, up from 1.15 percent in 2007. Virginia had the highest adoption rate of organic milk at 2.7 percent.

Extended life paper products. Average adoption rate of 67.5 percent, up from 50.77 percent in 2007. Minnesota had the highest adoption rate with 78.1 percent.

Concentrated/reduced-packaging liquid laundry detergents. Average adoption rate of 76.3 percent, up from 22.86 percent in 2007. Oklahoma led the category with an adoption rate of 96.3 percent.

To reflect the growing consumer preference for eco-friendly products, Wal-Mart said it will now track additional product categories, including sustainable coffee and eco-friendly cleaning products.