800,000 out of 7 billion. Someone can cancel the zeros and simplify that but it's approximately 8/70,000 people or 0.00011%. That's tiny.
Actually suicide rates aren't astonishingly low if you compare them to other causes of death. Like murder. People are twice as likely to kill themselves than kill someone else, and the ratio is even more massively skewed in developed countries. Moreover you're forgetting that for every successful suicide there are about seventy attempts. Making suicide one of the most serious social issues period, especially in developed countries, and especially if you control for those who lack the means to do so humanely without considerable risk (which is almost everyone) or for whom the motive is extremely rare, like children and those with dependants which often preclude it as an option; with those two groups alone accounting for a huge proportion of the population. Then you have folks confined in aged care facilities, hospitals, prisons and the like where they are constantly monitored and prevented from commuting suicide, though a short visit to any aged care facility in a poor neighbourhood will make it clear a large percentage would if they could.
How? Most of the world is in poverty, even like in the first world is difficult. So many bad things and so few good ones yet to say that suicide rates are low would be an understatement
Suicide is a complex issue so attributing it to any one cause would be silly, but the idea that people commit suicide because of poverty or life being difficult is too simple an explanation. Humans are genetically evolved to thrive in violent, ruthlessly competitive environments at the subsistence level. We have about a million years practise managing in environments that are materially worse than almost anything that currently exists on our planet, but to the extent that we can thrive under these circumstances we're designed to do so in close-knit bands with common goals. This is not a big feature of many progressive cultures. Though they may be materially rich people very rapidly get acclimatised to the material benefits or downsides of their circumstances. Their value is often relative; whether in abstract or real terms. For example even the poorest people in the US are still among the richest people on the planet, but their
relative poverty in their own country might mean they face more material hardship than many with far less wealth in poorer societies. Likewise all the abstractions we value are often subject to relative determinations of worth. No matter how lucky you may be there is always someone better off. We've also been conned
en masse into believing that the acquisition of money and goods is the key to happiness. It is not. While more and more now we're also being conned into believing that the value of our lifestyle is determined by the amount of social validation and envy it garners, even if only among strangers, with the two aims often being inextricably interconnected. It's highly profitable for people to think like this. Especially if, as in progressive countries, these things form self-perpetuating cultural cycles that can have real impacts on people's social, romantic and professional lives. Unfortunately they do not make people happy, and the pursuit of it often makes them miserable. While those who are 'out of the game,' entirely are often cut off from the very things that do make life worth living as they lack the requisite social pre-approval to be able to pursue the sort of meaningful relationships and the resources (social and financial) to pursue the sort of meaningful vocations which, in combination, do actually make people happy.
There are other issues as well. Honestly, so many it would take more time than I would like to spend thinking about it to go over them, but in places where suicide is a massive issue these seem to be the big ones.