Alright, I'll take a swing at this.
Lets go with the SINless first, being the lowest income. About 30% of the Sinless live Street lifestyles, about 40% live Squatter Lifestyles, and about 30% live Low Lifestyles. At least thats those that don't have a Fake SIN and/or are a Shadowrunner. So the average SINless person makes about 9600

a year. I'd say that the SINless people make up about 50% of the worlds population, with a huge majority of the average income being influenced by the "upper class" SINless.
Now for the Average Citizen with a SIN that isn't a Corps. Lets asume that about 60% have Low lifestyles, while around 45% have Medium lifestyles with about 5% having the High Lifestyle. That set the average income at about 48000

per year. This is probably around 15% of the world population.
And now the average Wageslave sellout. Lets go with about 20% in Low Lifestyles, 70% in Middle lifestyles, and 10% in High lifestyles. We get about 59000

per year for the average wageslave. These faceless suckers are probably about 35% of the World Population.
Finally, lets have a go at the world average just for shits and giggles. With the SINless at 50%, the norms at 15%, and the wageslaves at 35%; the world average is 32000
While this might not seem so bad, These "statistics" set the Homeless population of the world at about 35%. As far as I know, that is terrible. That would be about 2.3 Billion homeless if we went by our current population. This is likely a bit less since the world population was decimated by VITAS. I'm unsure as to the the exact number.... and it doesn't matter.