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

     Driver |
   Training |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        421        4.21        4.21
          1 |         60        0.60        4.81
          2 |          4        0.04        4.85
          3 |         20        0.20        5.05
          4 |         42        0.42        5.47
          5 |          1        0.01        5.48
          6 |         10        0.10        5.58
          9 |      9,442       94.42      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016