Two dates differences, results in years

I was reading the blog post on date class

in the post, I saw the following code:

Dim difference As Double = RightDate.TotalSeconds - d.TotalSeconds
Dim days As Integer
Dim years As Integer
Dim months As Integer
Dim dateResult As New date
dateResult.TotalSeconds = difference
days = dateResult.Day - 1
years = dateResult.Year - 1904
months = dateResult.Month - 1
Dim result As New Dictionary
result.Value(kDay) = days
result.Value(kYear) = years
result.Value(kMonth) = months
Return result

My question is, to get years difference I see they are taking the current year and subtracting by 1904
years = dateResult.Year - 1904

Just curious, why is the value 1904 and not something else?

1904 was originally the base year for macOS way way way back when
First leap year after a century or something

thank you norm for the sanity checkā€¦ I am in the process of calculating a persons age based on date of birth and when a report was generated. My goal was not to make them younger no older than their actual age :slight_smile: