Frequencies for first 10,000 rows of nprev12 variable in natl1986 dataset :

  Number of |
   Prenatal |
     Visits |
     Recode |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        214        2.14        2.14
          2 |        244        2.44        4.58
          3 |        447        4.47        9.05
          4 |        704        7.04       16.09
          5 |      1,017       10.17       26.26
          6 |      1,863       18.63       44.89
          7 |      2,430       24.30       69.19
          8 |      1,563       15.63       84.82
          9 |        925        9.25       94.07
         10 |        212        2.12       96.19
         11 |        239        2.39       98.58
         12 |        142        1.42      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016