When was the most violent time in history?

[THE FUGITIVE]

The most violent time in history, measured by the number of people killed by collective violence as a proportion of a) total number of deaths and b) total number of people who lived, was the 1st half of the 20th Century. See this answer for details.

The 119,515,000 deaths caused by war and oppression between 1900 and 1945, according to my calculations based on Matthew White’s list of man-made calamities, make up 4.72 % of the (1,656,000,000 + 3,390,198, 215 â€" 2,516,000,000 =) 2,530,198,215 people who died between 1900 and 1950, and 2.37 % of the (1,656,000,000 + 3,390,198,215 =) 5,046,198,215 people who lived in that period according to the chart in Carl Haub, How Many People Have Ever Lived on Earth?.

The current era is comparatively very peaceful. From by blog article Germs vs. guns, or death from mass violence in perspective:

However, as the 21st Century is into its fifteenth year, and despite the horrors of local conflicts that make international press headlines (like the "Islamic State" insurgency in Iraq and Syria) or do not (like the ongoing armed conflict in my native Colombia), war ranks low â€" some say lower than ever â€" as a worldwide cause of mortality, According to the WHO’s World Health Report 2004, "Annex Table 2 Deaths by cause, sex and mortality stratum in WHO Regions, estimates for 2002", in 2002 war was responsible for a total of about 172,000 deaths representing 0.3 % of the ca. 57,029,000 deaths in that year (about 1 in 333 deaths), vs. violence other than war (ca. 559,000, 0.98% or about 1 in 102), self-inflicted deaths (873,000, 1.53 % or about 1 in 65), unintentional injuries (ca. 3,551,000, 6.23 % or about 1 in 16), communicable diseases, maternal and perinatal conditions and nutritional deficiencies (18,324,000, 32.1 % or about 1 in 3) and non-communicable conditions (33,537,000, 58.81 % or about 1 in 2). The WHO’s Global status report on violence prevention 2014 mentions war in the following context:

Since 2000, about 6 million people globally have been killed in acts of interpersonal violence, making homicide a more frequent cause of death than all wars combined during this period. Non-fatal interpersonal violence is more common than homicide and has serious and lifelong health and social consequences.

An online algorithm based on WHO data shows war ranking way after each of traffic accidents, falls, drowning, poisonings, fires, other accidents, suicide and non-war violence as a cause of death from injuries.