Frequencies for first 10,000 rows of pain variable in nhamcsed1997 dataset :

 presenting |
   level of |
       pain |      Freq.     Percent        Cum.
------------+-----------------------------------
    Unknown |      4,268       42.68       42.68
       None |      1,597       15.97       58.65
       Mild |      1,985       19.85       78.50
   Moderate |      1,444       14.44       92.94
     Severe |        427        4.27       97.21
      Blank |        279        2.79      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016