Hi, Bill:
%SYSFUNC will allow you to use DATA step functions. However, it seems to me that %SYSFUNC is the wrong function to use in this context.
A very frequent use of %SYSFUNC is something more like this:
[pre]
title "Today is: %sysfunc(today(),mmddyy10.)";
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For what you want to do, you will have to get the summary number via another method (other than %SYSFUNC). The program below gets the average age of all the students in SASHELP.CLASS, by using PROC SQL and SELECT-INTO to create a macro variable which contains the average. Then, subsequent program steps can use that average in a TITLE statement (or in other statements). I just used a PROC PRINT instead of PROC GCHART, but you would be able to use the same technique with the Graph procedures. You just need to create a macro variable that holds your SUM -- before you use that macro variable in a TITLE statement.
cynthia
[pre]
proc sql;
select mean(age) format=5.2 into :avgage
from sashelp.class;
quit;
%let avgage = &avgage;
%put overall average age is: &avgage;
proc print data=sashelp.class;
title "Today is: %sysfunc(today(),mmddyy10.)";
title2 "The Average Age is &avgage";
run;
[/pre]