Frequencies for first 10,000 rows of f_u_primac variable in linkpe2009psden dataset :

    Primary |
C-Section U |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      6,582       65.82       65.82
          1 |      3,417       34.17       99.99
          2 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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