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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,140       21.40       21.40
          1 |        720        7.20       28.60
          2 |      1,203       12.03       40.63
          3 |      1,617       16.17       56.80
          4 |      4,126       41.26       98.06
          5 |         27        0.27       98.33
          6 |          1        0.01       98.34
          9 |        166        1.66      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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