Supplements as generally understood include vitamins, minerals, fiber, fatty acids, or amino acids, among other substances. U.S. authorities define dietary supplements as foods, while elsewhere they may be classified as drugs or other products. There are more than 50,000 dietary supplements available. More than half of the U.S. adult population (53% - 55%) consume dietary supplements with most common ones being multivitamins.
Wind power capacity has expanded to 369,553 MW by December 2014, and total wind energy production is growing rapidly and has reached around 4% of worldwide electricity usage.
Wind generators, or wind turbines, have become a popular symbol of clean carbon free electricity. Unlike other sources of renewable energy such as hydro-electricity or geothermal, wind and solar power are variable producers of electricity. Since the wind does not always blow nor the sun always shine, any given wind turbine will never produce its full capacity rating for an extended period of time.