Development refers to improvements in the conditions of people's lives, such as health, education, and income. It occurs at different rates in different countries. The U.S. underwent its own version of development when it became an independent nation in 1776:The average American earned about $1,000 a year in today's dollars, compared with $30,000 today.One in five children died before their first birthday, compared with about one in 143 today.Less than 50% of white children, and almost no black children, went to school; today almost all American children finish primary school.On average, Americans were about four times richer than the people of the world's poorest countries; they are 100 times richer today.Poor countries have experienced improvement as well. Over the past 50 years, there has been more progress in reducing poverty and improving health and education than at any other time in history. Over this period:Diseases such as smallpox and river blindness that formerly