Frequencies for first 10,000 rows of nprevis variable in natl1998 dataset :

      Total |
  Number of |
   Prenatal |
     Visits |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |        131        1.31        1.31
          1 |         36        0.36        1.67
          2 |         65        0.65        2.32
          3 |        109        1.09        3.41
          4 |        130        1.30        4.71
          5 |        176        1.76        6.47
          6 |        285        2.85        9.32
          7 |        345        3.45       12.77
          8 |        584        5.84       18.61
          9 |        530        5.30       23.91
         10 |      1,246       12.46       36.37
         11 |        660        6.60       42.97
         12 |      1,673       16.73       59.70
         13 |        629        6.29       65.99
         14 |      1,005       10.05       76.04
         15 |      1,507       15.07       91.11
         16 |        292        2.92       94.03
         17 |        136        1.36       95.39
         18 |        139        1.39       96.78
         19 |         39        0.39       97.17
         20 |        120        1.20       98.37
         21 |         20        0.20       98.57
         22 |         25        0.25       98.82
         23 |         14        0.14       98.96
         24 |         14        0.14       99.10
         25 |         35        0.35       99.45
         26 |          1        0.01       99.46
         27 |          1        0.01       99.47
         28 |          3        0.03       99.50
         29 |          1        0.01       99.51
         30 |         12        0.12       99.63
         32 |          1        0.01       99.64
         35 |          2        0.02       99.66
         36 |          1        0.01       99.67
         38 |          1        0.01       99.68
         40 |          3        0.03       99.71
         49 |          1        0.01       99.72
         99 |         28        0.28      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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