Frequencies for first 10,000 rows of pctpovr variable in namcs2008 dataset :

   percent poverty in patient's zip |      Freq.     Percent        Cum.
------------------------------------+-----------------------------------
                       missing data |        481        4.81        4.81
quartile 1 (less than 5.00 percent) |      2,372       23.72       28.53
     quartile 2 (5.00-9.99 percent) |      3,281       32.81       61.34
   quartile 3 (10.00-19.99 percent) |      2,767       27.67       89.01
 quartile 4 (20.00 percent or more) |      1,099       10.99      100.00
------------------------------------+-----------------------------------
                              Total |     10,000      100.00

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