A brief dig didn't get me to any cited data. They refer (without link) to "Global Rich List", which might be http://www.globalrichlist.com/.
Scrolling through all their infographics, I finally get to this: "For the income track, we've used the most recent (2008) statistics from the World Bank, based on household surveys. Here we rank you against the entire world population at the time of the surveys, estimated at 6.69 billion people."
Have you outsourced your brain to the first link in the google results? If there's something wrong with the logic of what I've written or the data sources I'm using, please point it out.
Just the number I found, what do you say it is? 71% of the world lives on less than $10 a day, average globally yearly income is less than $1,500. Even the worst off Americans are extremely well off comparatively to the majority of the world is my point.
The comment you are replying to is using the pigeonhole principle to cast doubt on your data by saying that there are more Americans with income over the 1% threshold you cite than can fit into 1% of the world's population.
I dug into the data behind your claim, briefly, and I think I ended at a self-reported survey. So, that data is probably wrong.
Scrolling through all their infographics, I finally get to this: "For the income track, we've used the most recent (2008) statistics from the World Bank, based on household surveys. Here we rank you against the entire world population at the time of the surveys, estimated at 6.69 billion people."