I cannot think of a simple option to do this with SGPLOT even with the latest release (SAS 9.4M2). GTL does have such an option at SAS 9.4 (TickValueHAlign). Similar option is coming in SG with SAS 9.4M3 (called ValuesHAlign). If you have SAS 9.3 or later, you can use Annotate to do this using the TEXT function.