Jimmy Fallon is still the king of late-night when it comes to young viewers, but his overall audience has shrunk since the end of 2016.

The good news for Stephen Colbert’s “Late Show” on CBS is that it beat Fallon’s “Tonight Show” on NBC in total viewers last week, for the first time since his debut in September 2015. The less good news is that the win came not necessarily just because Colbert’s live audience is growing at a fast clip, but because Fallon’s live audience is falling.

The start of 2017 has seen Fallon’s live total audience drop significantly from what it was pulling in at the end of 2016; the week of Thanksgiving and several weeks after brought in total viewership of around 3.5 million, with ratings in the advertiser-coveted 18-49 demographic hovering around a 0.9.

Last week, Colbert edged past Fallon in total viewers for the five-day frame, a surprise to late-night watchers that was chalked up to buzz for the focus on skewering the Trump administration that Colbert has brought to the show. In the 18-49 demo, Fallon still led Colbert last week by about two-tenths of a rating point.

Here are the ratings for the week of Jan. 30:

Show 18-49 Rating Total Viewers (MM)
Fallon 0.67 2.76
Colbert 0.48 2.77
Kimmel 0.45 2.06
Meyers 0.38 1.43
Corden 0.3 1.28

Colbert, Fallon and ABC’s “Jimmy Kimmel Live” all actually took a dip last week compared to the week leading into the Jan. 20 presidential inauguration (Colbert was in reruns the week after the inauguration). Here are the ratings for the week of Jan. 16:

Show 18-49 Total Viewers
Fallon 0.73 2.85
Colbert 0.52 2.84
Kimmel 0.5 2.26
Meyers 0.39 1.41
Corden 0.29 1.3

Nevertheless, that’s a fine start to the Trump era. Until you realize that it’s not much different than the pre-Trump era. Here are the current season-to-date averages for the broadcast late-night shows:

Show 18-49 Rating Total Viewers (MM)
Fallon 0.88 3.37
Colbert 0.56 2.95
Kimmel 0.5 2.25
Meyers 0.45 1.6
Corden 0.31 1.34

And here are the season averages for the shows as of Oct. 28, 2016, demonstrating how little movement there’s been since the election.

Show 18-49 Rating Total Viewers (MM)
Fallon 0.89 3.35
Colbert 0.58 2.82
Kimmel 0.5 2.28
Meyers 0.46 1.58
Corden 0.34 1.33

Season average total viewership for Colbert has increased in the intervening months by about 130,000 viewers. Yet younger viewers aren’t following the same trend — Colbert hasn’t seen any real movement in adults 18-49 since the election. CBS also notes that digital streams of “Late Show” are up 70% over the year-ago period (although they won’t disclose the actual numbers of streams).

The lack of major movement of the needle for Colbert and Kimmel seems to indicate that Fallon’s viewers aren’t switching their allegiance; they may simply be tuning out all together. Week-to-week ratings fluctuate in a quantum-like fashion. The real story lies not in the night-by-night battles, but the larger seasonal shifts.