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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,953       19.53       19.53
          1 |        740        7.40       26.93
          2 |      1,159       11.59       38.52
          3 |      2,016       20.16       58.68
          4 |      3,977       39.77       98.45
          5 |         22        0.22       98.67
          6 |          1        0.01       98.68
          9 |        132        1.32      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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