Frequencies for first 10,000 rows of pctpovr variable in namcs2009 dataset :

   percent poverty in patient's zip |      Freq.     Percent        Cum.
------------------------------------+-----------------------------------
                       missing data |        541        5.41        5.41
quartile 1 (less than 5.00 percent) |      2,448       24.48       29.89
     quartile 2 (5.00-9.99 percent) |      3,276       32.76       62.65
   quartile 3 (10.00-19.99 percent) |      2,654       26.54       89.19
 quartile 4 (20.00 percent or more) |      1,081       10.81      100.00
------------------------------------+-----------------------------------
                              Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016