Life can be a killer. And if you are a citizen of the US, it is slightly more lethal than it used to be: life expectancy in America has unexpectedly dipped. 

Statistics released last week showed that, in 2015, the average American could expect to reach the age of 78.8 years. The year before, it was 78.9. The loss of little more than a month does not sound like much, but a decline has not happened since 1993, when HIV/Aids and influenza combined to knock the country off track for a year. 

It bucks the upward trend that similarly advanced countries, such as Japan and Sweden, have enjoyed almost without interruption. Between 1840 and 2007, life expectancy in developed countries rose by about three months per year; most American babies born in 1900 failed to live past 50.