People confuse the richest 1% of America and the richest 1% of the world. The former is multimillionnaires, the latter is like, software engineers in America. This article concerns the latter.
The US is, give or take, 4% of the global population. So, the top income quintile ($153,000/yr and above) brings you to around 1% of the global population, with room for well-off people in other countries.
In case your math skills are rusty, the global 1% is 80 million people. That’s the same size as Germany, the country. Yes it includes oil barons, multinational CEOs, and whatnot, but also like, professionals in expensive cost-of-living areas like Californian software engineers.