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

underride/o |
    verride |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,914       99.14       99.14
          1 |         32        0.32       99.46
          2 |          7        0.07       99.53
          3 |         14        0.14       99.67
          4 |          2        0.02       99.69
          5 |          1        0.01       99.70
          6 |          1        0.01       99.71
          7 |         14        0.14       99.85
          8 |          3        0.03       99.88
          9 |         12        0.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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