With thanks to Paul of Pauls Studio for enlightening me - because I had not noticed!
Call myself a Social Media Manager, tsk... :)
Find Your Most Popular Post
If you hover over the stat which shows the 'number of people who saw this post' at the bottom of any status update, a pop up box will appear alerting you to the stats about the organic and viral reach of that post.
If it was a Promoted Post, you will also see the Paid reach.
At the bottom of the pop up box is the legend '*** people saw your most popular post' with the most popular post part hyperlinked.
Click through and it will take you to the status update that achieved the most views.
Why it's important to know your most popular Facebook status update
And why would you need to know that? Well so you can do more of the same! It works...