Frequencies for first 10,000 rows of nprev12 variable in natl1997 dataset :

  Number of |
   Prenatal |
     Visits |
     Recode |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         88        0.88        0.88
          2 |         96        0.96        1.84
          3 |        184        1.84        3.68
          4 |        459        4.59        8.27
          5 |        759        7.59       15.86
          6 |      1,844       18.44       34.30
          7 |      2,424       24.24       58.54
          8 |      1,663       16.63       75.17
          9 |      1,798       17.98       93.15
         10 |        266        2.66       95.81
         11 |        335        3.35       99.16
         12 |         84        0.84      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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