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

UNDERRIDE/O |
    VERRIDE |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,931       99.31       99.31
          1 |         20        0.20       99.51
          2 |          8        0.08       99.59
          3 |         12        0.12       99.71
          4 |          5        0.05       99.76
          6 |          3        0.03       99.79
          7 |         18        0.18       99.97
          8 |          1        0.01       99.98
          9 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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