In the 1970s, NASA conducted a number of summer studies to create artwork depicting the future of space colonies. At 10,000 people, these colonies housed slightly more people than the current three-person ISS crew.

That said, progress is being made. What, with six crew members scheduled for ISS duty in the near future, Earth will have literally doubled the population in orbit. Like I said, progress. Just 9,994 more to go. NASA NAS via MAKE]