OK here's a serious reply:
First you'd need to define violence, if you'd define violence as the amount of violence inside of any given society, North East Asian societies score the best, European societies right after them.
But if we take the graph - I figure this would be based on actual evidence, and would mean wars among sovereign nations, not genocide for example (example: Armenian genocide, genocide of Hindus, Jews, Christians, Africans under Islam, Pol Pot. juntas in Central / South America etc.)
For the past 4 500 years, there were only three societies that created civilizations with a high level of social cooperation and prosperity. Persian, Classical European and North East Asian. No other society in the past 4 500 years (with a possible exception of Inca / Aztec which was very cruel btw.) ever reached the point that a westerner understands as "civilized".
To find evidence of organized warfare elsewhere, where there was no civilization or written language in the first place, is certainly way more difficult (not to mention the historical population concentration - in the past prosperity meant more population, misery less - today it's exactly the opposite).
Most of the warfare documented in the past 4 500 years (which would be likely the case here) thus likely happened either among these three civilizations, or between them and others more primitive, but ruthless (Huns, Mongols, Islam) trying to subjugate them and take their wealth by force.
Hope this helps.
Btw. the original Arabs that were spreading Islam by sword from the Arabian peninsula were a semitic nation that was ethnically White (this is documented in the aHadith, also in many instances its explicitly noted that Mohammad was "white"). After they spread by the sword, more Islamic converts from the nations subjugated by Islam, that were non-white, were engaged in Jihad. Europe was hammered ruthlessly and also an estimated 1 million Europeans enslaved (for example even the famous writer Miguel Cervantes himself was enslaved for 5 years).
Here's a map of the Islamic expansion for illustration:
If you look for a body count related to the Islamic Jihad and further genocide of the Dhimmi (Christians, Jews) and other polytheist population under Islamic rule throughout the 1 400 years of history of Islam, it's not easy to get the exact numbers. If you'd look for a total amount of casualties (not just direct warfare casualties) one also needs to take into consideration such accounts such as Arabs running the original slave trade (slavery was a powerful tool to spread Islam and is still alive in some parts of the Islamic world).
The center for the study of political Islam came up with the following estimation (citation follows):
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Africa
Thomas Sowell [Thomas Sowell, Race and Culture, BasicBooks, 1994, p. 188] estimates that 11 million slaves were shipped across the Atlantic and 14 million were sent to the Islamic nations of North Africa and the Middle East. For every slave captured many others died. Estimates of this collateral damage vary. The renowned missionary David Livingstone estimated that for every slave who reached a plantation, five others were killed in the initial raid or died of illness and privation on the forced march.[Woman’s Presbyterian Board of Missions, David Livingstone, p. 62, 1888] Those who were left behind were the very young, the weak, the sick and the old. These soon died since the main providers had been killed or enslaved. So, for 25 million slaves delivered to the market, we have an estimated death of about 120 million people. Islam ran the wholesale slave trade in Africa.
120 million Africans
Christians
The number of Christians martyred by Islam is 9 million [David B. Barrett, Todd M. Johnson, World Christian Trends AD 30-AD 2200, William Carey Library, 2001, p. 230, table 4-10] . A rough estimate by Raphael Moore in History of Asia Minor is that another 50 million died in wars by jihad. So counting the million African Christians killed in the 20th century we have:
60 million Christians
Hindus
Koenard Elst in Negationism in India gives an estimate of 80 million Hindus killed in the total jihad against India. [Koenard Elst, Negationism in India, Voice of India, New Delhi, 2002, pg. 34.] The country of India today is only half the size of ancient India, due to jihad. The mountains near India are called the Hindu Kush, meaning the “funeral pyre of the Hindus.”
80 million Hindus
Buddhists
Buddhists do not keep up with the history of war. Keep in mind that in jihad only Christians and Jews were allowed to survive as dhimmis (servants to Islam) everyone else had to convert or die. Jihad killed the Buddhists in Turkey, Afghanistan, along the Silk Route, and in India. The total is roughly 10 million. [David B. Barrett, Todd M. Johnson, World Christian Trends AD 30-AD 2200, William Carey Library, 2001, p. 230, table 4-1.]
10 million Buddhists
Jews
Oddly enough there were not enough Jews killed in jihad to significantly affect the totals of the Great Annihilation. The jihad in Arabia was 100 percent effective, but the numbers were in the thousands, not millions. After that, the Jews submitted and became the dhimmis (servants and second class citizens) of Islam and did not have geographic political power.
This gives a rough estimate of 270 million killed by jihad.
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This is quite a staggering number given that most of this happened between 622 AD and 1924 AD (the end of the last Caliphate) thus with practically no weapons of mass destruction available.
The only Islamic genocide of non Islamic population that could be regarded as committed with advanced weapons was the Armenian genocide that was supposed to bring about 1.5 million casualties from 1914 - 1923.