Frequencies for first 10,000 rows of rept_cod_num variable in demo2010q2 dataset :

          rept_cod_num |      Freq.     Percent        Cum.
-----------------------+-----------------------------------
            DIR Direct |        553        5.53        5.53
EXP Expedited (15-Day) |      7,593       75.93       81.46
          PER Periodic |      1,854       18.54      100.00
-----------------------+-----------------------------------
                 Total |     10,000      100.00

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