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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,095       20.95       20.95
          1 |        617        6.17       27.12
          2 |      1,027       10.27       37.39
          3 |      2,065       20.65       58.04
          4 |      4,020       40.20       98.24
          5 |         37        0.37       98.61
          6 |          1        0.01       98.62
          9 |        138        1.38      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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