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

     Injury |
   Severity |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      1,806       18.06       18.06
          1 |        562        5.62       23.68
          2 |      1,396       13.96       37.64
          3 |      1,839       18.39       56.03
          4 |      4,367       43.67       99.70
          5 |         12        0.12       99.82
          9 |         18        0.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Apr 2016