For one, only about half of American table salt (which makes up 11% of the salt Americans consume today) is actually iodised.

首先，只有大约一半的美国食盐（占当今美国人消费的盐的 11%）是真正加碘的。

After trials showed that supplements of iodine could prevent goitre, iodised salt was rolled out commercially in 1924, starting in grocery stores in Michigan.

试验表明， 补充碘可以预防甲状腺肿，碘盐于 1924 年开始商业化销售，首先在密歇根州的杂货店销售。