Because you asked for the DEFAULT output dataset instead of telling the OUTPUT statement what you actually wanted.
This should generate a dataset that is much closer.
output out = PayGap mean=;
Read the documentation on what the OUTPUT statement can do.
If you are really desperate you could try using ODS OUTPUT statement to snag a copy of the data that the proc used to generate the printed report. But since that was structure designed to be PRINTED and not ANALYZED it will usually require a fair amount of work to make it useful.