Frequencies for first 10,000 rows of proc variable in nhamcsed2007 dataset :

  were procedures |
        provided? |      Freq.     Percent        Cum.
------------------+-----------------------------------
               no |      4,921       49.21       49.21
              yes |      4,632       46.32       95.53
entire item blank |        447        4.47      100.00
------------------+-----------------------------------
            Total |     10,000      100.00

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