In SAS^® 9.4M0 (TS1M0) to SAS^® 9.4M6 (TS1M6) and SAS^® Viya^® 3.5, the default value for the YEARCUTOFF= system option is 1926. Beginning in SAS^® 9.4M7 (TS1M7) and later, along with the SAS^® Viya^® platform, the default value for the YEARCUTOFF= system option is 1940. SAS releases prior to SAS 9.4M0 have a default value of 1920 for the YEARCUTOFF= system option.   

You can change the value of YEARCUTOFF by adding an option to your SAS config file (affecting all users and programs) or by using an OPTIONS statement in your affected SAS program. SAS recommends that you set the value to 1940 to be consistent with the shipped default value beginning in SAS^® 9.4M7 (TS1M7) and beyond, along with the SAS Viya platform. 

The YEARCUTOFF= system option is used when processing two-digit years to determine the century for SAS date values. The YEARCUTOFF= option specifies the first year of a 100-year span. For example, using the default value of YEARCUTOFF=1926, two-digit years of 26 through 99 are assigned a century prefix of "19" (for example, 1926–1999), and two-digit years from 00 through 25 are assigned a century prefix of "20" (for example, 2000–2025).

For detailed information about the YEARCUTOFF= system option, see SAS System Options: Reference. Further details about SAS date, time, and datetime values can be found in The Year 2000 in SAS Language Reference: Concepts.