In LIC's/NEE's there is an i in the percentage of people who live in urban areas as supposed to rural areas as migration into the cities is high for work (more work oppotunities in the than the countryside). An example/case study used is often Brazil and Rio de Janerio.
In HIC's the opposite occurs, are choosing to live in rural or suberb areas as more people now either work from home or can commute daily into a city for work (furher due to good transport links). You can often use London or your local area as a case study for this one.
Hope this helps