Mexico is a nation in transition with a population of over 120 million people. Historically, the population was around 18-25 million before the Spanish conquest but doubled in the 19th century. In the 20th century, Mexico lost around 2 million people and currently experiences migration of 450,000 people per year to the US. In the early 20th century, 90% of Mexicans lived in rural areas but urbanization led to 51% living in Mexico City by the 1960s. Today, around 3/4 of Mexicans live in cities with Mexico City being one of the largest metropolitan areas in the world. Catholicism is the dominant religion in Mexico with 90% of the population identifying as Catholic. Protestantism and Buddhism also