Frequencies for first 10,000 rows of pctpovr variable in nhamcsed2008 dataset :

 percent pop below poverty level in |
                 patient's zip code |      Freq.     Percent        Cum.
------------------------------------+-----------------------------------
                       missing data |        565        5.65        5.65
quartile 1 (less than 5.00 percent) |      1,431       14.31       19.96
     quartile 2 (5.00-9.99 percent) |      2,548       25.48       45.44
   quartile 3 (10.00-19.99 percent) |      3,519       35.19       80.63
 quartile 4 (20.00 percent or more) |      1,937       19.37      100.00
------------------------------------+-----------------------------------
                              Total |     10,000      100.00

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