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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,356       23.56       23.56
          1 |        727        7.27       30.83
          2 |      1,147       11.47       42.30
          3 |      1,310       13.10       55.40
          4 |      4,312       43.12       98.52
          5 |         22        0.22       98.74
          6 |          1        0.01       98.75
          9 |        125        1.25      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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