http://fr.wikipedia.org/wiki/Esp%C3%A9rance_de_vie
In the area of statistics, life expectancy at age x can be defined not only for populations of living beings and organisms, but also for objects, instruments, organizations, etc.
So we can talk well life expectancy at the heart of life, flat on my words therefore ... BUT generally currently the most used data is life expectancy at age 0 therefore at birth ... and this one is fixed for each past year!
http://fr.wikipedia.org/wiki/Esp%C3%A9r ... ie_humaine
Thus, contrary to what the title "life expectancy" might suggest, it is not a forecast as to the probabilities of death in subsequent years: say for example that the life expectancy of men in 2000 is 75 years does not mean that men born in 2000 will live on average 75 years. They will live on average 75 years only if the mortality conditions they will meet throughout their life will match those of the year 2000. So, if progress continues, men born in 2000 should live on average more 75 years old. But it is also possible that conditions will deteriorate in the future.
This card looks good life expectancy at birth for children born in 2007: http://commons.wikimedia.org/wiki/File: ... ctancy.png
After determining your own life expectancy at age X (knowing that a lot of past things have already influenced your life) is, in my opinion, as valid as a forecast by madam sun ...