Frequencies for first 10,000 rows of dr_train variable in vehicle dataset :

     Driver |
   Training |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        283        2.83        2.83
          1 |        160        1.60        4.43
          2 |          1        0.01        4.44
          3 |          2        0.02        4.46
          4 |          7        0.07        4.53
          5 |          1        0.01        4.54
          6 |          4        0.04        4.58
          9 |      9,542       95.42      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016