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

  Eclampsia |
        RFP |
690=f_urf_e |
  clamp U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         38        0.38        0.38
          2 |      9,956       99.56       99.94
          9 |          6        0.06      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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