Around 2000 in Germany: https://www.bvnw.de/natur-und-waldkindergaerten/deutschland

450-500 in Denmark here's a good research study including impact on ongoing educational attainments: https://nexs.ku.dk/forskning/idraet-individ-samfund/krop-lae...

About 1000 in the US: https://naturallykatey.wordpress.com/2021/01/08/list-of-fore...

Plenty in the UK, Spain and France too.

There are more projects for early years education than later, and they very typically don't have websites or much digital presence.