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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,951       19.51       19.51
          1 |        601        6.01       25.52
          2 |      1,224       12.24       37.76
          3 |      1,914       19.14       56.90
          4 |      4,143       41.43       98.33
          5 |         42        0.42       98.75
          6 |          3        0.03       98.78
          9 |        122        1.22      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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