I remember it was 55.
Had a co-worker who inflicted that on his poor stuck at home family.
Carter awlays liked to let you know he was an enginneer & had been trained in the Navy Nuclear program. In action he was remarkably ill-informed about enegy & energy production. I have a feeling he was actually a crappy submarine nuclear prolusion engineer hence his brief Navy career.
I looked it up, though I hate to post a link to the New York Times. Here it is:
HOWEVER, there may well have been a different edict for nighttime. I didn’t want to spend that much time at the New York Times and just went with the headline :)