How Concentrated are Countries' Populations?

I thought that an interesting way to explore population would be to visualize how concentrated in one city the populations of countries are. You can see how in India and China, the two countries with the largest population, their largest city makes up a relatively small portion of their overall population. Yet, smaller countries like Indonesia, exhibit similar percentages as well, which is interesting. South America appears to have the highest concentration of people in their largest city.