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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,893       18.93       18.93
          1 |        730        7.30       26.23
          2 |      1,209       12.09       38.32
          3 |      1,735       17.35       55.67
          4 |      4,215       42.15       97.82
          5 |         19        0.19       98.01
          6 |          1        0.01       98.02
          9 |        198        1.98      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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