Indicates the earliest two-digit year that you want Excel to interpret as being in the twenty-first century. For example, ...

Indicates the earliest two-digit year that you want Excel to interpret as being in the twenty-first century. For example, if you enter 40, Excel interprets the years 00 through 39 as 2000 through 2039 and the years 40 through 99 as 1940 through 1999.

Accepts: whole number from 4 through 99.