Frequencies for first 10,000 rows of pttinr variable in nhamcsed2010 dataset :

Prothrombin |
   time/INR |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,074       90.74       90.74
        yes |        926        9.26      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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