You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "what was the average life expectancy in the roman empire?" whose answer is late-50s.
Each document should contain about 30 words, and these documents should contain useful information.

Query: average life expectancy roman empire
Useful Output:

Doc 1: Roman emperors had an average life expectancy of about 51 years. This figure is roughly what would be expected for any group of Roman men who
Doc 2: Comments230. myysterio2. Seeing an emperor penguin in a chart of average life expectancy of Roman emperors is now my favorite told in stone
Doc 3:  life expectancy of around 51 years (the life expectancy in the Roman Empire was about 25 years). At first, this might confirm our
Doc 4: Estimation of infant mortality and life expectancy in the time of the Roman Empire: a methodological examination  life tables lead to an average level of 20
Doc 5: People in ancient Rome. The average age at death today in the United States is about 82, while in the Roman Empire it was probably about 35.