Frequencies for first 10,000 rows of f_mpcb_u variable in natl2006 dataset :

      Month |
   Prenatal |
 Care Began |
      (mpcb |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         11        0.11        0.11
          1 |      9,989       99.89      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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