Frequencies for first 10,000 rows of nprevis variable in natl1992 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        133        1.33        1.33
          1 |         48        0.48        1.81
          2 |         88        0.88        2.69
          3 |        137        1.37        4.06
          4 |        186        1.86        5.92
          5 |        257        2.57        8.49
          6 |        389        3.89       12.38
          7 |        442        4.42       16.80
          8 |        599        5.99       22.79
          9 |        565        5.65       28.44
         10 |      1,420       14.20       42.64
         11 |        745        7.45       50.09
         12 |      1,805       18.05       68.14
         13 |        715        7.15       75.29
         14 |        749        7.49       82.78
         15 |        663        6.63       89.41
         16 |        377        3.77       93.18
         17 |        178        1.78       94.96
         18 |        164        1.64       96.60
         19 |         64        0.64       97.24
         20 |        108        1.08       98.32
         21 |         24        0.24       98.56
         22 |         23        0.23       98.79
         23 |          5        0.05       98.84
         24 |          4        0.04       98.88
         25 |         37        0.37       99.25
         26 |          3        0.03       99.28
         27 |          2        0.02       99.30
         28 |          3        0.03       99.33
         30 |         14        0.14       99.47
         32 |          2        0.02       99.49
         33 |          1        0.01       99.50
         34 |          1        0.01       99.51
         35 |          2        0.02       99.53
         40 |          4        0.04       99.57
         45 |          1        0.01       99.58
         48 |          1        0.01       99.59
         49 |          3        0.03       99.62
         99 |         38        0.38      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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