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

     Driver |
   Training |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        602        6.02        6.02
          1 |        295        2.95        8.97
          2 |         47        0.47        9.44
          3 |          2        0.02        9.46
          4 |          1        0.01        9.47
          5 |          6        0.06        9.53
          9 |      9,047       90.47      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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