Frequencies for prev_spd variable in vehicle dataset :

   PREVIOUS |
   SPEEDING |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        414       76.10       76.10
          1 |         44        8.09       84.19
          2 |         19        3.49       87.68
          3 |         16        2.94       90.63
          4 |          2        0.37       90.99
          5 |         12        2.21       93.20
         99 |         36        6.62       99.82
          . |          1        0.18      100.00
------------+-----------------------------------
      Total |        544      100.00

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