put on the payroll vs sign up

put on the payroll

sign up

verb

To add one's own name to the list of people who are participating in something (including amateur, but not professional, teams)
To agree to purchase some good or service.
To add a name to the list of people who are participating in something.

How often have the words put on the payroll and sign up occurred in a corpus of books? (source: Google Ngram Viewer )