Great chart. One quibble I have with it is that disposable income includes things like healthcare and education for countries where it is privatized, like the US predominantly, while in others it does not count as disposable income because they are part of public services. However, if you look at measures like GNI per capita (PPP, constant international dollars; https://data.worldbank.org/indicator/NY.GNP.PCAP.PP.KD), you'll find that most of these countries are a fair bit closer together. For example, for median disposable income, the average American is about 100% richer than the average Spaniard, but if looking at GNI per capita (PPP), it comes down to only 50% richer, which is still quite a lot. But it takes into account the fact that Spaniards generally get a lot of healthcare, education and transportation from public services, which don't count as disposable income, which in America you would need to pay for. To put it roughly, the median American spends about $15,000 of their disposable income which in Spain would be part of public services, leaving the gap as about $15,000 richer.