Frequencies for first 10,000 rows of nprevis variable in natlterr1999 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |         85        0.85        0.85
          1 |         37        0.37        1.22
          2 |         80        0.80        2.02
          3 |        130        1.30        3.32
          4 |        228        2.28        5.60
          5 |        340        3.40        9.00
          6 |        509        5.09       14.09
          7 |        681        6.81       20.90
          8 |        826        8.26       29.16
          9 |        662        6.62       35.78
         10 |      1,814       18.14       53.92
         11 |        588        5.88       59.80
         12 |      1,715       17.15       76.95
         13 |        486        4.86       81.81
         14 |        510        5.10       86.91
         15 |        662        6.62       93.53
         16 |        233        2.33       95.86
         17 |         83        0.83       96.69
         18 |        133        1.33       98.02
         19 |         35        0.35       98.37
         20 |         93        0.93       99.30
         21 |         16        0.16       99.46
         22 |          4        0.04       99.50
         23 |          6        0.06       99.56
         24 |          1        0.01       99.57
         25 |         12        0.12       99.69
         26 |          3        0.03       99.72
         29 |          1        0.01       99.73
         30 |          1        0.01       99.74
         34 |          1        0.01       99.75
         37 |          1        0.01       99.76
         38 |          4        0.04       99.80
         39 |          2        0.02       99.82
         40 |          2        0.02       99.84
         41 |          1        0.01       99.85
         99 |         15        0.15      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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