PCTPRIM

You can specify AUTO or an integer from 1 through 100.
UNLOAD PLUS ignores this option for referenced files.
For large table spaces, the primary allocation that PCTPRIM calculates might be too large. To override the calculated value, specify the MAXPRIM option. For more information, see the description of the MAXPRIM option.
Specifying the default
You can specify the default for the PCTPRIM command option in your installation options module by using the PCTPRIM installation option. UNLOAD PLUS was shipped with a default value of AUTO for this option. The command option overrides the default that is in the installation options module.
AUTO
If you specify AUTO for SMS allocations, UNLOAD PLUS uses the largest available extent as the value for the primary allocation. For non-SMS allocations, specifying AUTO is equivalent to specifying a value of 100.
integer
You can specify an integer from 1 through 100.