This website is pretty interesting. If you enter your annual salary, it takes World Bank data, and calcluates roughly where you stand in terms of global wealth. From the research I’ve done, this website’s methodology seems pretty accurate.
If you’re interested in fooling around for a few minutes, give it a try. You can find it here.
P.S. I’m not trying to convince anybody that they need to donate to whatever cause it is that they’re shilling for, my interest was merely in their calculating machine.