Frequencies for first 10,000 rows of bnp variable in nhamcsed2013 dataset :

      Brain |
natriuretic |
    peptide |      Freq.     Percent        Cum.
------------+-----------------------------------
         No |      9,727       97.27       97.27
        Yes |        273        2.73      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 7 Nov 2016