When using the "statistiche di riepilogo" you will be automatically generating PROC MEANS code. Unfortunately, PROC MEANS does not support custom percentiles as you're asking for. You can, however, use some other procedures such as PROC UNIVARIATE or PROC STDIZE. I recommend PROC STDIZE but you can see examples of both used in this blog post.
Here's a [slightly modified] snippet of code running the STDIZE procedure as you are looking for.
proc stdize data=sashelp.cars PctlMtd=ORD_STAT outstat=StdLongPctls
pctlpts=15;
var mpg_city mpg_highway;
run;
proc print data=StdLongPctls noobs;
where _type_ =: 'P';
run;
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