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

     INJURY |
   SEVERITY |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      2,109       21.09       21.09
          1 |        731        7.31       28.40
          2 |      1,289       12.89       41.29
          3 |      1,666       16.66       57.95
          4 |      4,039       40.39       98.34
          5 |         56        0.56       98.90
          6 |          1        0.01       98.91
          9 |        109        1.09      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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