Observed (1851 to 2011) and projected (2011 to 2061) annual average growth rate, natural increase and migratory increase in Canada per intercensal period Two factors are behind population growth: natural increase and migratory increase. 1  Natural increase is the difference between the number of births and deaths during a given period. 2  Migratory increase is the difference between the number of immigrants entering the country and the number of emigrants leaving the country.
Why do we have wisdom teeth? Adults can have up to 32 teeth. The wisdom teeth are the last to appear, right at the back of the mouth. They usually appear when you are between 17 and 25, although sometimes they appear many years later. People often have jaws that are too small for all 32 teeth to fit - 28 is often the most we have room for.
Wisdom teeth are the upper and lower third molars, located at the very back of the mouth. They are called wisdom teeth because usually they come in between ages 17 and 21âwhen a person is old enough to have gained some wisdom. Wisdom teeth that are healthy and in the right position usually don't cause problems.