/* listyrv macro
   lists variables for requested years, taking into
   account years where no PSID interviews were done
   
   From 1968 to 1997 interviews were every year.
   From 1999 to 2009 interviews are odd years.
*/
%macro listyrv(vname,begy=1968,endy=&maxyr);
    %do year=&begy %to &endy;
        %let yr=%substr(&year,3,2);
        %if (&year ge 1968 and &year le 1997) or
            (&year>1997 and %index(13579,%substr(&year,4,1))>0) %then %do;
            &vname&yr
        %end;   
    %end;
%mend;