Between 2020 and 2050, positive average annual growth rates have been projected for Australia, New Zealand, the United States of America and Canada. The projected growth in these countries relates to an expectation of continuing positive net overseas migration and the younger age of the current population in these countries. In contrast, the populations of Italy, Greece, and Japan are projected to decrease in size. The populations of countries from the less developed regions are projected to continue increasing but with gradually declining average annual growth rates. Between 2000 and 2050, the population of Papua New Guinea is projected to double in size while those of Viet Nam, Malaysia and Indonesia are projected to increase by at least half.
More developed regions comprise Northern America, Japan, Europe, Australia and New Zealand.