Extensive nationwide IQ tests were administered to 72,780 Thai students from December 2010 to January 2011. The average IQ was found to be 98.59, which is higher than previous studies have found. IQ levels were found to be inconsistent throughout the country, with the lowest average of 88.07 found in the southern region of Narathiwat Province and the highest average of 108.91 reported in Nonthaburi Province. The Ministry of Public Health blames the discrepancies on iodine deficiency, and  steps were being taken to require that iodine be added to table salt, a practice common in many Western countries.