The red bar indicates the season average in millions of viewers per episode.
The blue bar indicates last week's average.

A few things to notice:
All of them have fallen in the ratings department.
Corden and Meyers which follow immediately after Colbert and Fallon have about half the viewers changing channels after their lead-in.
The other half were probably asleep.
Conan and Noah are doing so badly, they will probably be yanked or not renewed.

Since all of these shows have been riding the "hate Trump" bandwagon, don't expect their ratings to rise again - they are only going down.
Fallon used to consistently dominate all the others.  NBC must be pissed at him.

To summarize, these libtard clowns are all losing.  People are tired of their crap.
Libtards are also beginning to cannibalize their own - much like piranhas do.  They most recently are sacrificing their support of Kathy Griffin and Slippery Hillary Clinton.

**By the way, a couple of weeks ago, I was invited by Nielsen Research - which compiles the ratings - to be one of their "Nielsen Families". 
I should have made a copy of the invitation to show you.. but I sent it back in.  They should be sending me more stuff in the near future and I will be sure to share that with you.