Frequencies for first 10,000 rows of blodpres variable in nhamcsopd1993 dataset :

      blood |
   pressure |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,611       46.11       46.11
          1 |      5,389       53.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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