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

    Roadway |
      Grade |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         26        0.26        0.26
          1 |      7,299       72.99       73.25
          2 |        312        3.12       76.37
          3 |        104        1.04       77.41
          4 |         13        0.13       77.54
          5 |        653        6.53       84.07
          6 |        854        8.54       92.61
          8 |        662        6.62       99.23
          9 |         77        0.77      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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