I was fairly close with most of my guesses, except for the last two. I really overestimated the number of people who practice religions that are not Christianity, Islam, Hinduism, or Buddhism. I also thought that only about 1% of the world is atheist. I had no idea the number was so much higher, even more than Buddhists and almost as much as Hindus. Christians are still the most common, which didn't surprise me. What did surprise me was that Judaism isn't even on the chart. I thought it was at least as common as Hinduism.
I totally underestimated the number of people who live in cities. I'd always assumed there were much more rural areas than urban areas, but I guess urban areas by definition are more populated, so that makes up for it. The rest of the class seems to have gotten it right, though.
I guess I underestimated how many kids there are under 14 and overestimated how many people there are over 65. I was pretty close with 15-65, though. It looks like most people thought the three numbers were much closer together, whereas I assumed they were much farther apart.