Frequencies for first 10,000 rows of rept_cod_num variable in demo2007q3 dataset :

          rept_cod_num |      Freq.     Percent        Cum.
-----------------------+-----------------------------------
            DIR Direct |        672        6.72        6.72
EXP Expedited (15-Day) |      8,103       81.03       87.75
          PER Periodic |      1,225       12.25      100.00
-----------------------+-----------------------------------
                 Total |     10,000      100.00

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