Frequencies for first 10,000 rows of pctpovr variable in nhamcsopd2010 dataset :

   percent poverty in patient's zip |      Freq.     Percent        Cum.
------------------------------------+-----------------------------------
                       missing data |        401        4.01        4.01
quartile 1 (less than 5.00 percent) |      1,356       13.56       17.57
     quartile 2 (5.00-9.99 percent) |      2,430       24.30       41.87
   quartile 3 (10.00-19.99 percent) |      3,956       39.56       81.43
 quartile 4 (20.00 percent or more) |      1,857       18.57      100.00
------------------------------------+-----------------------------------
                              Total |     10,000      100.00

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