The World Bank updated GDP PPP data for the world's economies on Thursday. Russia is now fourth largest (ahead of Japan and Germany), while China is first.
Isn't GDP PPP per capita the relevant metric? I guess I don't know how to think about GDP PPP at a certain point aren't we just measuring which country has more people
GDP PPP measures something closer to the real value being consumed. It's how big the economy is in a more tangible metric.
Adding per-capita to it answers where people are doing the best, economically, on average. And you're just going to get Luxembourg and Liechtenstein and Norway and Qatar at the top of that list. But a smaller country having a higher average is less significant than the same for a larger country. If you want to see how much clout a country's economy has, and maybe get a proxy for its tax base, you use GDP PPP. If you want to say "my economy could stretch further than your economy", you use GDP PPP.
How much the acknowledged income of the top 10% is higher than the lowest 10% (so 6,7 means the top 10% have nearly 7 times the income - not wealth! - of the lower 10% of incomes in terms of households of the country. Top income households are typically smaller - in terms of persons per household, not in terms of square meter per household -, so if you look at it from a per person view it will be even worse from our perspective)