Frequencies for first 10,000 rows of fed_aid variable in accident dataset :

Federal-Aid |
     System |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        972        9.72        9.72
          2 |      3,111       31.11       40.83
          3 |        818        8.18       49.01
          4 |      1,961       19.61       68.62
          5 |        242        2.42       71.04
          6 |        162        1.62       72.66
          7 |        702        7.02       79.68
          8 |      2,002       20.02       99.70
          9 |         30        0.30      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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