What's the best time to join?

I'm always wondering when is the ideal time of day (or day of the week) to join Multiplayer and not find only the lobsterpot running. Anyone else seeking for this wisdom? Is there any statistic of player activity in MP games throughout time?
If not, it would be best averaged in around one-hour intervals for every day of the week.

Quite helpful, thanks! So, the peak time is around 20:00 to 21:00 UTC and peak days are the weekend. I guessed it's gonna be around this time, but wanted a more precise information.