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

  were procedures |
        provided? |      Freq.     Percent        Cum.
------------------+-----------------------------------
               no |      4,826       48.26       48.26
              yes |      4,759       47.59       95.85
entire item blank |        415        4.15      100.00
------------------+-----------------------------------
            Total |     10,000      100.00

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