As you can see from the map, more developed regions of the world generally have higher life expectancies (green) than less developed regions with lower life expectancies (red). The regional variation is quite dramatic.
However, some countries like Saudi Arabia have very high GNP per capita but don't have high life expectancies. Alternatively, there are countries like China and Cuba that have low GNP per capita have reasonably high life expectancies.
Life expectancy rose rapidly in the twentieth century due to improvements in public health, nutrition and medicine. It's likely that life expectancy of the most developed countries will slowly advance and then reach a peak in the range of the mid-80s in age. Currently, microstates Andorra, San Marino, and Singapore along with Japan have the world's highest life expectancies (83.5, 82.1, 81.6 and 81.15, respectively).
Unfortunately, AIDS has taken its toll in Africa, Asia and even Latin America by reducing life expectancy in 34 different countries (26 of them in Africa). Africa is home to the world's lowest life expectancies with Swaziland (33.2 years), Botswana (33.9 years) and Lesotho (34.5 years) rounding out the bottom.
Between 1998 and 2000, 44 different countries had a change of two years or more of their life expectancies from birth and 23 countries increased in life expectancy while 21 countries had a drop.
Women almost always have higher life expectancies than men. Currently, the worldwide life expectancy for all people is 64.3 years but for males it's 62.7 years and for females life expectancy is 66 years, a difference of more than three years. The sex difference ranges from four to six years in North America and Europe to more than 13 years between men and women in Russia.
The reasons for the difference between male and female life expectancy are not fully understood. While some scholars argue that women are biologically superior to men and thus live longer, others argue that men are employed in more hazardous occupations (factories, military service, etc). Plus, men generally drive, smoke and drink more than women - men are even more often murdered.
Historic Life Expectancy
During the Roman Empire, Romans had a approximate life expectancy of 22 to 25 years. In 1900, the world life expectancy was approximately 30 years and in 1985 it was about 62 years, just two years short of today's life expectancy.
Life expectancy changes as one gets older. By the time a child reaches their first year, their chances of living longer increase. By the time of late adulthood, ones chances of survival to a very old age are quite good. For example, although the life expectancy from birth for all people in the United States is 77.7 years, those who live to age 65 will have an average of almost 18 additional years left to live, making their life expectancy almost 83 years.