Did some basic analysis on the NijiNE girls schedules for this week, using last weeks if it hasn't been updated yet. It was quick math so I might have miscounted 1 or 2 but for the most part it should be accurate, i included the schedules so feel free to correct if wrong.

tldr - 5/10 have 50% or higher collab rates, 3/10 have 40-49%, 2 have 33% collab rates. None have less than 1/3 of their streams as collabs.
This is a ridiculously higher percentage of collabs even for their lowest streamer and it needs to stop.

Elira
>6 Solo streams (assuming no surprise collabs in yuhioh or minecraft or her celebration, unlikely)
>3 collabs
>33% collab rate assuming no drop-ins.

Pomu
>2 solo streams
>2 collabs
>24 hours stream which will have guaranteed collabs
>60% collab rate on numbers, far more if counting amount of hours streamed

Finana
>2 solo streams
>1 solo member stream (watch along)
>3 collabs
>50% collab rate, 60% for non-members

Rosemi
>3 solo streams
>4 collabs
>guerilla maybe
>57% collab rate

Petra
>3 solos
>1 member solo
>3 collabs
>50% collab rate for non-members, 42% for members

Selen (schedule for this week not updated as of this post)
>3 solo streams
>1 member stream (unknown)
>2 collabs
>40% collab rate (membership stream unknown, not listed as she has collabed during them in the past)

Millie (not updated as of this post)
>6 solo streams
>4 collabs
>40% collab rate
>unlisted vod rate not counted for this list

Enna
>2 solo streams
>1 solo membership stream
>1 collab
>33% collab rate for non-members, 25% for members

Nina
>4 solo streams
>1 unknown
>4 collabs
>50~% collab rate, dropins not included

Reimu
>4 solo streams
>3 collab streams
>42% collab rate