you cant make the assumption that patterns of small boat crossing follow the same pattern
I was just looking at the shape of the graph lines year by year
Broadly speaking they look like this:
Every year the count starts from 0 and increases until it reached December in the right of the graph and is eg 10k or 20k or 30k etc
The more you get every month throughout the year, the steeper the line is. Winter is very low activity
Suppose instead that these guys did all their coming over in Jan and dec, 20k in Jan, 20k in dec and 0 the rest of the year. A hypothetical (pink) line might look like:
Steep for jan and dec, flat the rest
Lets slice the actual graph:
Roughly roughly, on the vertical that represents "by jun25th", in 2021, about 5000 crossings. In 2023, about 10k so twice as bad, but then maybe heroic effort, weather etc, the latter part of the year really knocked down the crossings and the line flattened out to finish at nearly 2021 levels.
2025, is about 20k
There is a broad trend on the graph, looking at the curves, of an S shape, generally higher than the year before. If 2025 follows that same shape, and offset by the amount it's already describing as a multiplier of any other line of choice, you get to an estimate of about 60k maybe