Misleading. The life expectancy numbers cited by OP are grossly skewed because of one critical issue: infant mortality. Sure, people are living longer, but not that much longer.
The lower life expectancies in recent years were due in part to high infant mortality [1], but my understanding is that infant mortality rates have been low and stable for too long [2] for further decline to completely account for the continuing uptrend in life expectancy we've been seeing.
Also, the decline in infant mortality isn't monotonic. Besides making it more likely that sick newborns survive their various conditions, new medical technology also makes it possible to save some infants who previously would have been recorded as stillborn. Children born prematurely are more than ordinarily likely to die during infancy (all this new technology is, y'know, new), so the infant mortality statistic goes up.
though, so the infant mortality numbers rise on balance.
[1] Although autopsies on the Egyptian mummies has shown tha life was pretty horrific back then. People really did die of old age in their 30s and 40s. Even the rich were somewhat malnourished by our standards. Paleopathologists believe that just about everyone carried a whole ecosystem of nasty parasites, and started experiencing symptoms we associate with old age (particularly arteriosclerosis, loss of bone and muscle mass) around 25 years of age.
Infant mortality hasn't changed a lot in Western countries since the 1960's. In 1960 it used to be 25 deaths/1000 live births, now it is around 10 but this is nothing compared to 100 in 1915; see http://www.marchofdimes.com/images/ihs_img017.gif
The end of the baby boom, I suppose; the infrastructure was there to take care of a lot more children but since the number of children dropped and the infrastructure wasn't donwsized, the quality of care increased. But that's just a guess.
