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

Federal-Aid |
     System |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        968        9.68        9.68
          2 |      3,078       30.78       40.46
          3 |        782        7.82       48.28
          4 |      2,033       20.33       68.61
          5 |        509        5.09       73.70
          6 |        112        1.12       74.82
          7 |        765        7.65       82.47
          8 |      1,551       15.51       97.98
          9 |        202        2.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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