how rare are power Brakes ?

I have had 24 A-bodies (67-74) in the decade+ I have been into Cars and I have NEVER had one with power brakes. The later ones all have manual disk.

Even among the B-bodies (68- 70) I have or have had ...I have only seen ONE ever with power brakes and it's a high optioned GTX

I have had a few with power steering but even that is hit and miss.

I just saw another thread with someone talking about an A-body power brake booster and I thought it has to be rare having never had one in an A body.

Are there many power brake A-bodies out there??