Frequencies for first 10,000 rows of previs_rec variable in natl2007 dataset :

  Number of |
   Prenatal |
     Visits |
 Recode U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         35        0.35        0.35
          2 |        227        2.27        2.62
          3 |        412        4.12        6.74
          4 |        722        7.22       13.96
          5 |      1,294       12.94       26.90
          6 |      1,939       19.39       46.29
          7 |      2,077       20.77       67.06
          8 |      1,145       11.45       78.51
          9 |        893        8.93       87.44
         10 |        191        1.91       89.35
         11 |        400        4.00       93.35
         12 |        665        6.65      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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