At best, a tough subject to broach.

Always a controversial topic, even when intelligence tests were first invented -- and keeping in mind that IQ scores only measure a very narrow set of cognitive skills -- we (the actual researchers, that is) are only just beginning to understand the true functions and power of the human brain, the mind (the consciousness as well as the unconsciousness), and this through the study of multiple forms of current and past, as well as proposed cognizant intelligences (glad I got a thesaurus…).

Suffice to say that intelligence levels may be income-driven. If one lives in a wealthy community, access is available to excelled learning courses that likely include philosophic reasoning. An average IQ for most tests centers on a score of 100, meaning anything below 100 would be lower than average, and anything above 100 would therefore be above. At the same time, a genius is anyone with a score of 140 and above.

As a sidenote, and with a score of 198, Evangelos Katsioulis, MD, MSc, MA, Ph.D., has the highest tested IQ level in the world, according to the World Genius Directory. This rather outgoing Greek psychiatrist happily holds other degrees in philosophy and medical research technology.

Anyway, upon this meager globe we all share, the most common IQ level (approximating 68 percent of the population) varies between 85 and 115. Those that remain range out the higher and lower IQs, with about 16 percent below 85 and only 3 percent actually under 70. On the other hand, about 16 percent are above 115, with a bare 3 percent reaching above 130.

Bear in mind that children can be outright mean and utterly degrading to each other (pay attention), especially if such outbursts are generally ignored.

Therefore, it becomes probable to assume (a likely dangerous word) that persons with lower IQs may at times develop feelings of inadequacy and anger, leading to violence, though more often, with patience and proper education, usefulness and value, leading to sanguinity's overall status quo. Persons with average IQs at times develop feelings of mediocrity and anger, leading to violence, though more often, with patience and proper education, usefulness and value, leading to sanguinity's overall status quo. At times, persons with higher IQs develop feelings of superiority and anger, leading to violence, though more often, with patience and proper education, usefulness and value, leading to sanguinity's overall status quo.

My point is (finally) while percentages may approximate some level of constancy, our global population continues to rise, resulting in more and more high and low IQs, many of whom are improperly handled and improperly educated, and so demand an immediate change to the real world of unfair averages with the use of some form of equalizing outburst (fists, knives, handguns).

My Google Search on the topic - "IQ Population":

IQ of US population
By this definition, approximately two-thirds of the population scores are between IQ 85 and IQ 115. About 2.5 percent of the population scores above 130 and 2.5 percent below 70. Scores from intelligence tests are estimates of intelligence.

Which countries have the lowest IQ?

The countries with the lowest average IQ scores are Equatorial Guinea, Cameron, Mozambique, Saint Lucia, The Gambia, The Republic of Congo, Saint Kitts and Nevis, Liberia, Haiti and Gabon. All of these countries have an average IQ of less than 70.