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

      month |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        729        7.29        7.29
          2 |        706        7.06       14.35
          3 |        729        7.29       21.64
          4 |        729        7.29       28.93
          5 |        869        8.69       37.62
          6 |        875        8.75       46.37
          7 |        832        8.32       54.69
          8 |      1,051       10.51       65.20
          9 |        834        8.34       73.54
         10 |        887        8.87       82.41
         11 |        875        8.75       91.16
         12 |        884        8.84      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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