Frequencies for first 10,000 rows of drug1cl3 variable in nhamcsopd2004 dataset :

        drug class #3 for medication #1 |      Freq.     Percent        Cum.
----------------------------------------+-----------------------------------
                         ace inhibitors |          1        0.01        0.01
                       topical steroids |          1        0.01        0.02
               dermatitis/antipruritics |          1        0.01        0.03
                     topical analgesics |          1        0.01        0.04
                        anticonvulsants |         18        0.18        0.22
ocular anti-infective/anti-inflammatory |         11        0.11        0.33
                   otic, topical (misc) |          1        0.01        0.34
                                  nsaid |          1        0.01        0.35
                           antipyretics |         70        0.70        1.05
         antiasthmatics/bronchodilators |          2        0.02        1.07
   antitussives/expectorants/mucolytics |          1        0.01        1.08
                         antihistamines |         18        0.18        1.26
                          cold remedies |          3        0.03        1.29
                    pharmaceutical aids |          2        0.02        1.31
                          surgical aids |         76        0.76        2.07
                                      . |      9,793       97.93      100.00
----------------------------------------+-----------------------------------
                                  Total |     10,000      100.00

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