No, the statistics are pretty clear: The share of all parents who were on p/maternal leave during the 2018 microcensus. They don't claim anything else and are a pretty good approximation: How big a share of p/maternal leave offered do fathers and mothers take.

"which I commonly see" is not something that is statistically sound. And neither is just multiplying it. If fathers would on average take 1 month out of 24 offered this wouldn't exactly count as a success for the programme or gender equality.