Frequencies for first 10,000 rows of urf_phyper variable in natl2008 dataset :

  Pregnancy |
 Associated |
Hypertensio |
      n RFP |
689=f_urf_p |
  hyper U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        595        5.95        5.95
          2 |      9,399       93.99       99.94
          9 |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 May 2016