Frequencies for first 10,000 rows of pbamorer variable in nhamcsopd2008 dataset :

  percent pop w/bachelor's degree or |
        higher in patient's zip code |      Freq.     Percent        Cum.
-------------------------------------+-----------------------------------
                        missing data |        474        4.74        4.74
quartile 1 (less than 12.84 percent) |      2,851       28.51       33.25
    quartile 2 (12.84-19.66 percent) |      2,337       23.37       56.62
    quartile 3 (19.67-31.68 percent) |      2,274       22.74       79.36
  quartile 4 (31.69 percent or more) |      2,064       20.64      100.00
-------------------------------------+-----------------------------------
                               Total |     10,000      100.00

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