It will depend on what the basis is. Is it the number of birthdays that the person has in a year? If yes, then the right answer to this is 1. If it is the number of birthdays that the man will have in his lifetime, it will depend on how long he will live. The lifespan of persons has changed considerably over the past years.
There was a time when people are considered to be ancient when they reach the age of 50. There are a lot of diseases back then that did not have the proper medications and treatment yet. Humans are expected to live longer now. Some can prolong their life further by living a healthy lifestyle.