That's rude... Source? It's definitely not the CIA Factbook:
https://www.cia.gov/library/publications/the-world-factbook/...
Takeaway: EU GDP > America GDP ( don't forget, also the Euro vs USD rose since the start of 2018) ;)
https://www.cia.gov/library/publications/the-world-factbook/...
Takeaway: EU GDP > America GDP ( don't forget, also the Euro vs USD rose since the start of 2018) ;)
https://www.thebalance.com/dollar-to-yuan-conversion-and-his...
https://www.thebalance.com/how-does-china-influence-the-u-s-...
https://www.cluteinstitute.com/ojs/index.php/IBER/article/do...
However I haven't read them thoroughly, so I suggest you invest some time in doing some research.
P.S. I really hate this source/citation discourse that is effectively taken over every debate on the internet opinions can be constructed out of vast amounts of information and experience and even casual observations tend to be the product of much more information that can be distilled into bit size pieces.
Just do research and learn, stay away from wikipedia and go for academic and sources and don't shy from even biased opinion pieces as those tend to be some of the most valuable as they expose you to concrete positions and being wrong or right does not change their value.
That means that if you're an econ PhD and you tell me a basic statement, I'll trust it in real life. On the internet you'd have to prove you're a PhD first. It really does limit the conversation we can have. A lot of the time I find myself talking to someone (or arguing with them) and realizing they don't have the framework to hold the conversation - they'd need to read a half dozen books and do some intensive study because they want to work through problems that have already been solved.
On a more anecdotal side the people I tend to "trust" the least at least on the internet are those who often come out with citations for everything and dump a huge wall of text.
The problem with the internet is that you can find a citation for everything, I can find that enough citations that lizard aliens are actually the ones who control the exchange rate of the Yuan to the Dollar using a weather machine.
The credibility of sources is also extremely hard to determine these days especially in subjects which are not your primary proficiency it's too easy to publish anything you want these days even in reputable sources.
My point was partially that if I encounter you in another environment, I can quickly and easily assess whether you have the required proficiency, even if I don't possess it. It's much harder to do that online, at least at the moment.
I can't always do my own research, as I don't have the time to build a framework of knowledge that would allow me to do it efficiently, much less brute force it. All I can do is ask people I know who are very well educated in a field or read an abstract.
Why would I read comment sections if I'd already had the time and been able to find high quality sources to learned about the topic?
If you don't feel like citing sources, or don't have any good ones handy, saying so is fine. But even providing the right terms to search can be helpful!