Frequencies for first 10,000 rows of blodpres variable in nhamcsopd1997 dataset :

      blood |
   pressure |
       test |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,800       48.00       48.00
          1 |      5,200       52.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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