Frequencies for first 10,000 rows of ilp variable in natl2011 dataset :

   Interval |
 Since Last |
  Pregnancy |
RFP 571=? R |      Freq.     Percent        Cum.
------------+-----------------------------------
          . |     10,000      100.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015