What is the Base Version of the Google Play Services on Android 9.0 Pie?

[Android Central Question]

I´m right now with Android 8.0 and I have the Google Play services version updated on 15.0.90, but Im able to do a downgrade to 12.8.74 as the base version. I would like to know the base version on Android 9.0 if it can still be downgraded to 12.8.74 or lower?
Thanks for your time.