You can take a point of reference from the funding history - https://www.crunchbase.com/organization/kaggle#/entity $11M Nov 2011 followed by 1.75M in Sept 2015. The first was an amazing raise for their stage. Obviously pretty smart people and an area people wanted a part of . Appears the later was a bridging round as it's been tagged Series A like the first.
They laid off 1/3 staff earlier in 2015: https://www.wired.com/2015/02/data-science-darling-kaggle-cu...
That was 7 of 20 roles. They're now more like ~80 employees, according to LinkedIn. However, admittedly a lot aren't tagged right (investors, advisors, interns and people associated with Kaggle). Either way, appears the pivot in 2015 worked.
So you can straight-line from there. That's circa 3-5x employee growth over 3 years, which you can conjecture at least has a relationship with actual growth. That's not too shabby either. With growth over that timeframe and stage you'd probably be more interest in the story over the last 6-12 months, which is harder to gauge. It may have plateaued, it may have spiked.
So if you anchor the Series A at, say, 20% of the value. Then multiply out growth, then put a multiple on that you're looking at 100 at the low end and maybe 500 at the high-end. Likely somewhere square in the middle.
That's guesswork, but gives a ballpark view.