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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,053       20.53       20.53
          1 |        671        6.71       27.24
          2 |      1,142       11.42       38.66
          3 |      1,986       19.86       58.52
          4 |      3,986       39.86       98.38
          5 |         49        0.49       98.87
          6 |          1        0.01       98.88
          9 |        112        1.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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