Frequencies for first 10,000 rows of spiromet variable in nhamcsopd1994 dataset :

 spirometry |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,949       99.49       99.49
          1 |         51        0.51      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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