Frequencies for first 10,000 rows of inj_sev variable in person dataset :

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,187       21.87       21.87
          1 |        688        6.88       28.75
          2 |      1,324       13.24       41.99
          3 |      1,687       16.87       58.86
          4 |      4,005       40.05       98.91
          5 |         28        0.28       99.19
          9 |         81        0.81      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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