Pages lifetime on different period
<p>I'm trying to set the better cache duration for the news on my website, for this I need to learn more on my stats website. How can I return the average lifetime of a news knowing they are not published in the same time? </p>

<p>By lifetime I mean the duration between the "first" day (at least 1 view) to the "last" day (where there is no more view (or less than 2-3 by day)).
I have not page group, so I need to deal with this url part: "/news_xxx".</p>

<p>Thanks</p>