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

     Driver |
   Training |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        192        1.92        1.92
          1 |         46        0.46        2.38
          2 |          9        0.09        2.47
          3 |         17        0.17        2.64
          4 |         87        0.87        3.51
          5 |          4        0.04        3.55
          6 |          7        0.07        3.62
          9 |      9,638       96.38      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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