Excel dates about bad-data-guide HOT 2 OPEN

@calvinmetcalf could you post an example of the issue you're describing (is it this one?)

from bad-data-guide.

Yes the dates are stored as number counting from "1899-12-31" (is day 1).
Seems the didn't consider that if year is divisible by 100 it is not a leap year.

Fun fact - there is a second date system used by excel for mac which starts on "1904-01-01" (day 1)
(https://support.microsoft.com/en-us/help/214330/differences-between-the-1900-and-the-1904-date-system-in-excel - interesting they don't mention the leap year bug there... - but surprisingly the difference is 4 years and 1 day)

from bad-data-guide.