Frequencies for first 10,000 rows of rept_cod_num variable in demo2004q3 dataset :

          rept_cod_num |      Freq.     Percent        Cum.
-----------------------+-----------------------------------
            DIR Direct |      1,000       10.00       10.00
EXP Expedited (15-Day) |      7,158       71.58       81.58
          PER Periodic |      1,842       18.42      100.00
-----------------------+-----------------------------------
                 Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Dec 2015