All credits: Genesis Mining on the Medium platform.
Why should this subject even interest you? Well unless you have absolutely no savings in a bank, it should because it explains how much of your money actually still (or was) stored there.
The only addition I can add to this very well written 12 November 2019 blog is a 26th March 2020 U.S. Federal Government decision,…. that kind of changes the meaning and name of this form of banking, from…
‘Fractional Reserve Banking’ to ……
‘Zero Reserve Banking’!!

https://genesismining.medium.com/
https://www.federalreserve.gov/monetarypolicy/reservereq.htm