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

Federal-Aid |
     System |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |      1,028       10.28       10.28
          2 |      3,155       31.55       41.83
          3 |        853        8.53       50.36
          4 |      2,065       20.65       71.01
          5 |        216        2.16       73.17
          6 |         88        0.88       74.05
          7 |        650        6.50       80.55
          8 |      1,920       19.20       99.75
          9 |         25        0.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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