This variable is used to implement "date windowing" for Acu4GL. This variable determines which two-digit years will be considered to be in the twentieth century, and which two-digit years will be considered to be in the twenty-first century.
This variable accepts a two-digit value. Two-digit years that are smaller than this value are considered part of the twenty-first century (2000 is added to these dates).
Two-digit years that are equal to or larger than this value are considered to be in the twentieth century (1900 is added to them).
The default value for this variable is "20".