About 1970, when I started my accounting practice we used an IBM Service Bureau in Michigan. We used a full key board adding machine with optic font and a magnetic ink ribbon. We would update each client’s general ledger every month by printing on the paper tape the account number and then each transaction (plus for debit and minus for credit). We mailed the adding machine tape to the Service Bureau and they mailed back the financial statements. It produced great financial statements just as we produce today.