Frequencies for first 10,000 rows of nprev12 variable in natl1999 dataset :

  Number of |
   Prenatal |
     Visits |
     Recode |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        138        1.38        1.38
          2 |         99        0.99        2.37
          3 |        221        2.21        4.58
          4 |        447        4.47        9.05
          5 |        706        7.06       16.11
          6 |      1,655       16.55       32.66
          7 |      2,466       24.66       57.32
          8 |      1,745       17.45       74.77
          9 |      1,896       18.96       93.73
         10 |        256        2.56       96.29
         11 |        330        3.30       99.59
         12 |         41        0.41      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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