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

    roadway |
      grade |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         65        0.65        0.65
          1 |      6,774       67.74       68.39
          2 |        256        2.56       70.95
          3 |        102        1.02       71.97
          4 |         24        0.24       72.21
          5 |        679        6.79       79.00
          6 |        846        8.46       87.46
          8 |      1,191       11.91       99.37
          9 |         63        0.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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