Average US Water Pressure

I'm trying to figure out the average static water pressure for all homes in the US and also the standard deviation from that average. What percentage of people live with <30 PSI, how many with >70? Do any homes deal with pressures below 20 PSI?

It would be great if someone could point me to a bell curve for all of this info but if anyone could even just make their best guess I would very much appreciate it.

code states any building with pressure over 80 psi needs to be regulated. homes with copper pipe will usually have a pressure of 60-65 psi. homes with plastic pipe are usually set around 50-55 psi. your home should have a regulator on the main