I was rather surprised by this claim. Isn’t it currently beyond our ability to detect earth-sized planets around other stars? Isn’t it also beyond our capability to directly detect surface conditions on planets around other stars?
25% sounds way too high. We have not even found many stars like our own with rocky Earths like our own yet. I am certain we will eventually find them, but I think the number of rocky planets with oxygen atmosphere and liquid water is going to be under 1%.
Life is most likely rare but abundant- 1% of 100 billion is a butt-ton of Earths
Note that, while some are super-earths, others like Kepler-438b or the planets in the TRAPPIST-1 system are Earth-sized or smaller.
For astronomers "earth like" is just about anything within an order of magnitude of earths size and within the very vague habitable zone, it doesn't say anything about it's surface conditions.