On April 17, Tony Dokoupil ended his 15th week as anchor of the CBS Evening News — the same amount of time that the newscast’s previous anchors, John Dickerson and Maurice DuBois, had this season.

Dokoupil is still drawing more viewers than the tail end of Dickerson and DuBois’ tenure. But the anchor’s average audience has been falling recently, and the lead over the previous iteration of the CBS Evening News is shrinking.

In three of the past four weeks, the CBS Evening News has fallen under 4 million viewers per night, with a low of just over 3.5 million in the week of March 23. (For ratings numbers in this story, THR is including all weeknight airings of network evening newscasts, including those retitled for Nielsen classifying purposes.) ABC’s and NBC’s evening newscasts have also come in below their recent averages in that time, but the gap between second-place NBC and third-place CBS remains persistently large.

Since Dokoupil took over as anchor on Jan. 5 — as CBS News editor-in-chief Bari Weiss’ first high-profile change within the division — the CBS Evening News has averaged about 4.13 million total viewers and 521,000 in the core news demographic of adults 25-54, per Nielsen. In the first 15 weeks of the season, Dickerson and DuBois averaged about 4.02 million viewers and 498,500 in the 25-54 demo.

The past four weeks have been rougher: Since March 23, the CBS Evening News has drawn just 3.78 million viewers and 479,000 adults 25-54, declining 11 percent in both measures from Dokoupil’s prior average. Those are somewhat steeper drops than for ABC’s World News Tonight (-3 percent in both viewers and 25-54) and the NBC Nightly News (-7 percent in viewers, -9 percent in 25-54) in the past four weeks.

ABC has held its first quarter lead among the network newscasts in recent weeks, averaging 8.33 million viewers and 1.04 million adults 25-54 since March 23. The NBC Nightly News comes in at 6.29 million viewers and 920,000 adults 25-54.