Frequencies for first 10,000 rows of pttinr variable in nhamcsed2008 dataset :

prothrombin |
   time/inr |      Freq.     Percent        Cum.
------------+-----------------------------------
         no |      9,259       92.59       92.59
        yes |        741        7.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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