As a country develops, the inhabitants usually become wealthier-and healthier. They have better health care, drink cleaner water, and eat better food. Both men and women can expect to live longer. For example, table a shows that in Japan the average life expectancy at birth for men is 81.4 years, and for women is 87.5 years. On the other hand, in a developing country like Zambia, it is just 38.5 for men and 38.7 for women.