In most regions of the world where iodine is supplemented as iodized table salt and through iodization of water supply, the prevalence of iodine deficiency has declined. However, in areas where the soil is low in iodine and supplementation programs have not been implemented, the prevalence of iodine deficiency is still high. Other dietary sources of iodine include seafood (e.g., cod, bass, haddock, and perch) and kelp. Dairy products, eggs, and produce grown in iodine-rich soil can also be good food sources of iodine, but the quantity of iodine in these sources is difficult to measure.