I have always known that New York, especially New York City, has an extremely diverse population.  Mr. Salvo did not only reinforce these ideas, but similarly to the idea of evolution, proved that this diverse population is never constant or ceasing to change.

1. How can we know the true population of New York City because the census will never 100 percent accurate?

2. Out of pure curiosity, why are people leaving the New York City area all together?