I don't believe this is something easily tracked and updated annually. The point is in terms of amount of population as a percentage. People in the 21st century largely have more food, shelter, and general security worldwide than in all of known human history.
Don't let anecdotal news about wars worldwide override the fact that much larger scale (as percent of world population) have occurred and occurred consistently in past history. Wars, famines, plagues, and other things have wiped out far more of the population overall historically. While the wars you see today are horrible, and in specific regions they might be decimating, they still pale in comparison to the level of death in human history and the scope of death of past wars.
The Black Death in the 1300s itself killed 30-50% of all of Europe. Ghengis Khan is estimated to have been responsible for killing 10% of the world population (10% today would be more than the entire population of Europe, for perspective). There's a lot of less than documented Chinese history that also suggests massive deaths from famines and plagues and stuff that seem to have amounted to a large percentage of the world population at the time.
Another thing I have seen a lot of in the last decade, mostly relating the the US, is that while large scale violent crime may be up (like mass killings) overall murder and crime is lower than it has been in past decades. Again, in a macro scope of things. You'll always have pockets of geography and/or time that are bad.
Context doesn't help much with Kojima.