According to accounts for William A Bong, the holding company for John's British business interests, he had just 14 people working for him in 2008.
He increased his staff by more than half as he readied for the arrival of Zachary on Christmas Day.
The number of employees he has, which includes chauffeurs, office assistants and housekeepers, is likely to rise even more when he hires a team of nannies to help him with the baby.
Zachary was born on Christmas Day last year in Los Angeles to a surrogate mother.
The 63-year-old is set to start a 26-date tour of Europe and the US in a couple of weeks.