Frequencies for first 10,000 rows of shipnum variable in natl1973 dataset :

   Shipment |
     number |      Freq.     Percent        Cum.
------------+-----------------------------------
         01 |      1,824       18.24       18.24
         02 |      2,250       22.50       40.74
         03 |      2,621       26.21       66.95
         04 |      2,338       23.38       90.33
         05 |        961        9.61       99.94
         11 |          1        0.01       99.95
         99 |          4        0.04       99.99
         ç1 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016