Very cool but not as informative as it might appear in some ways. From what I can gather (by Googling a bit to find the stats he's using) he seems to be using a

Very cool but not as informative as it might appear in some ways. From what I can gather (by Googling a bit to find the stats he's using) he seems to be using a mix of means and medians and they're coming from different sources and different years. This isn't the best idea, but might be unavoidable. Despite being the most prosperous nation in history, that chart would make us look destitute. Using different forms of averages hides an extremely significant factor: our income gap. While good by world standards, it's poor-to-mediocre by developed nation standards and getting worse. I'd argue it's the biggest threat to our long-term stability because it compounds all of the others, but I suppose that's getting off-topic.