Keep in mind that you need to know the duration of transactions as well as the volume. Eg, the time between an employee getting paid and the employee paying re

Keep in mind that you need to know the duration of transactions as well as the volume. Eg, the time between an employee getting paid and the employee paying rent, or a construction project being funded and the materials purchased. If $1 trillion worth of transactions happen per year and each transaction lasts a month you need around $100 billion in currency. Ten years between transactions and you need $10 trillion. If there is less than a day between money being received and spent you need maybe $3 billion worth of currency to support a transaction volume of $1 trillion per year.