Life expectancy is the average number of years a hypothetical person in a specific group of people, who would be subject to the mortality rates of a specific period, could be expected to live. It is expressed in years.
How long a person can expect to live is based significantly on their quality of life, which stems partially from where they live. Generally speaking, people living in richer, more developed countries are expected to live longer. Clearly, life expectancy is lower in areas that have problems such as war, famine, disease, and reduced access to healthcare. In more developed countries where access to healthcare is more readily available life expectancy tends to be higher; as a country develops, predictions for life expectancy increases for all genders. In parts of the world where life expectancy is low, fertility rates tend to be higher and population tends to be increasing.
A person's sex is another factor that contributes to how long a person can be expected to live, although the size of this effect varies by country. In 2002, it was reported that the average Canadian woman lived to be 82 years old, whereas the average man lived to be 77. Although the reason why this occurs is not explicitly known, it may be partially due to the fact that men are more likely to die from some of the leading causes of death than women. Specifically, men are more likely to die from respiratory cancer, liver cirrhosis, prostate cancer, and heart disease than women. As well, men have a higher suicide rate and accidental death rate than women.
Below is a map generated using data from the World Bank showing the changes in life over the years. Overall, life expectancy has increased in all parts of the world over the past 50 years, however there are still areas around the world where life expectancy is significantly lower.