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

     Driver |
   Training |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        396        3.96        3.96
          1 |         36        0.36        4.32
          2 |          2        0.02        4.34
          3 |         13        0.13        4.47
          4 |         39        0.39        4.86
          5 |          1        0.01        4.87
          6 |         11        0.11        4.98
          9 |      9,502       95.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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