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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,961       19.61       19.61
          1 |        713        7.13       26.74
          2 |      1,282       12.82       39.56
          3 |      1,738       17.38       56.94
          4 |      4,073       40.73       97.67
          5 |         64        0.64       98.31
          9 |        169        1.69      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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