Iodine Jan 2013
60 ml of potassium iodate, costing about US$1.15 (in 2006), are required to iodise a ton of salt.

Switzerland has been increasing: 3.75 mg/kg in 1952, 7.5 mg/kg in 1962, 15 mg/kg in 1980, and 20 mg/kg in 1998.

Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of mental retardation.[1] According to public health experts, iodisation of salt may be the world's simplest and most cost-effective measure available to improve health, only costing US$0.05 per person per year

FDA 150 micrograms of iodine per day for both men and women

http://www.iccidd.org/pages/protecting-children/fortifying-salt/history-of-salt-iodization.php 
Several international groups have made recommendations, which are fairly similar. ICCIDD, WHO, and UNICEF recommend the following daily amounts:

            age 0-7 years, 90 micrograms (mcg)
            age 7-12 years, 120 mcg
            older than 12 years, 150 mcg
            pregnant and lactating women, 200 mcg

http://www.iodine-test.com/2012/01/history-and-use-of-iodized-salt.html 
The iodine content of U.S. and Canadian iodized salt is 100 ppm, or 77 µg iodine/g sodium chloride, while it is generally 20-40 ppm in other countries

It would take two grams (2,000 mg) of iodized salt in the U.S. to reach the daily recommended amount of iodine (150 µg) for non-pregnant adults. A majority of salt consumed in the U.S. comes from processed foods that do not typically use iodized salt. Unless meals are prepared at home with branded iodized salt, the chance of supplying the body with enough iodine daily will significantly decrease. New dietary guidelines for Americans now recommend a decrease in salt consumption from 2.3 to 1.5 g/day, potentially resulting in a decrease in iodine intake and an increase in people suffering from iodine deficiency.

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http://www.lef.org/magazine/mag2011/oct2011_The-Silent-Epidemic-of-Iodine-Deficiency_01.htm  LEF  Oct 2011
In 2008, researchers concerned about the growing threat of iodine deficiency analyzed 88 samples1 of iodized table salt—the main supply of this critical micronutrient for most people.2

Less than half of those tested contained amounts of iodine sufficient for optimal health.

Coupled with the trend of reduced salt consumption, rates of iodine deficiency are now reaching epidemic levels.

In the developed world, iodine deficiency has increased more than fourfold over the past 40 years. Nearly 74% of normal, “healthy” adults may no longer consume enough iodine.3,4

mean urinary iodine levels (a measure of iodine sufficiency) plummeted by more than half over a 20-year period.4,1

Food and Nutrition Board of the Institute of Medicine has set the tolerable upper limit at 1,100 mcg.18,23,24

By way of comparison, the average daily Japanese consumption of iodine ranges from 5,280 to 13,800 mcg of iodine, with no harmful effects and a host of benefits.18,25,2

Iodine deficiency disorders can produce symptoms of low thyroid function (hypothyroidism) even without abnormalities in measured thyroid hormone levels.34 Recent evidence suggests, for example, that iodine deficiency is linked to obesity, cognitive impairment, psychiatric disorders, fibromyalgia, and a variety of cancers.34

Paradoxically, another major consequence of mild-to-moderate iodine deficiency in older adults is hyperthyroidism (excessive thyroid function), especially in women.35 This is the result of rapidly growing thyroid gland nodules that over-produce thyroid hormone; it can trigger cardiac arrhythmias, osteoporosis, and muscle wasting.35

!!Table 2. Prevalence of Iodine Deficiency in Australia 3
Group|% With Mild Deficiency|% With Moderate to Severe Deficiency|Total % Deficient
Pregnant Women|29.6|19.8|49.4
Postpartum Women| 34.6|19.2|53.8
Diabetic Patients|37.8|34.1|71.9
Normal Volunteers|47.4|26.3|73.7||

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http://www.iodineonmymind.com/ 
the entire 1 pound Morton salt container only has, supposedly, 37 mg of iodine.  Dr. Brownstein recommends 50 mg/day of iodine, not the insignificant 0.15 mg/day.  The coastal Japanese have been taking the equivalent of 100 mg/day of iodine for thousands of years in the form of kelp.  They have far fewer chronic diseases and cancers than the Japanese (and non-Japanese) living in the USA.

!!Iodination of irrigation water as a method of supplying iodine to a severely iodine-deficient population in Xinjiang, China. 
Lancet. 1994 Jul 9;344(8915):107-10.  
Cao XY, Jiang XM, Kareem A, Dou ZH, Abdul Rakeman M, Zhang ML, Ma T, O'Donnell K, DeLong N, DeLong GR. Xinjiang Health and Anti-Epidemic Station, Urumchi.

Severe iodine deficiency still occurs in many countries, and causes cretinism and mental impairment. In southern Xinjiang province, China, after usual methods of iodine supplementation had failed, we iodinated irrigation water to increase iodine in soil, crops, animals, and human beings. 5% potassium iodate solution, dripped into an irrigation canal for 12 or 24 days, increased soil iodine 3-fold, and __crop and animal iodine 2-fold__. Median urinary iodine excretion in children increased from 18 to 49 micrograms/L (two groups of similar age). The cost for iodine was US $0.05 per person per year. Soil iodine remained stable over one winter, and dripping of iodine during the second year (US $0.12 per person per year) resulted in a further 4-fold increase in soil iodine and a 1.8-fold increase in iodine in crops. We conclude that iodination of irrigation water is an advantageous and cost-effective method of supplying iodine in southern Xinjiang, and may be useful in other areas dependent on irrigation.

http://www.iodineonmymind.com/weather 
The goal of the RDA for iodine is the prevention of extreme stupidity (cretinism), iodine-deficiency induced goiter and hypothyroidism, not whole body sufficiency for iodine.

reported in 1975 that iodine in dog food is 20 times higher than iodine in food consumed by humans. The amount of iodine in the food supply of humans, of pets and laboratory animals, expressed as parts per million (PPM) are: for humans 0.12; for rabbits 0.59; for rats 1.17 and for dogs 2.25. Schroeder commented:

"Because it is doubtful that man differs much in his needs from other omnivorous animals, we could build up a good, if very indirect, case that man is not getting enough”

During the period when potassium iodate was used as a dough conditioner (1960-1980), and prior to the introduction of the goitrogen bromate as an alternative to iodate (1), one slice of bread contained the full RDA for iodine

When a tablet form of Lugol is ingested at a daily amount of 50 mg elemental iodine, whole body sufficiency is achieved in approximately 3 months and the estimated amount of iodine retained in the body is approximately 1.5 gm

"some people are especially sensitive to the adverse effects of iodine". He is correct. Just as some people are sensitive to Vitamin C, some are sensitive to iodine/iodide. Few holistic physicians would deny the effectiveness of mega doses of Vitamin C, in amounts thousands of times greater than the RDA for Vitamin C, in the treatment of wide range of illnesses. Just as with Vitamin C therapies, individualized doses and proper follow-up visits can help minimize adverse effects of iodine/iodide therapies.

The most common adverse effects of iodine/iodide supplementation observed at the Center for Holistic Medicine has been metallic taste in the mouth and acne. Based on the experience of three clinicians at that Center, with a combined patient population of some 4,000, the __prevalence of these side effects is about 1%__. This is probably due to a detoxification reaction. The release of bromide may be one cause of this detoxification reaction.

Goiter is the enlargement of the thyroid in response to extremely low iodine intake. 

Iodized salt is the mainstay for prevention of goiter, therefore anyone who is not using adequate amounts of iodized salt in his diet will most likely be deficient in iodine because iodine occurs in such small quantities in food.

Since the thyroid gland is the most effective iodine-trapping organ in the body, the appearance of a goiter will be one of the very last signs of iodine deficiency.  Before a goiter occurs there will likely be many other signs and symptoms of iodine deficiency such as fibrocystic breast disease, ovarian cysts, skin problems, atherosclerosis, decreased mental status, depression, and fatigue.

[http://www.huffingtonpost.com/2011/06/01/iodine-deficiency_n_870000.html 
Iodine Deficiency Could Spell Big Problem For UK] June 2011
less than 5 percent of salt sold in the UK is iodized,

In the 1930s, iodine was added to cattle feed to improve milk production. This "unplanned contaminant," as Pearce describes it, had the happy effect of upping the iodine levels in dairy milk -- so much so that in the mid 1990s, researchers estimated it accounted for approximately 40 percent of the iodine intake in the UK.