Frequencies for first 10,000 rows of exp_dt_num variable in drug2004q4 dataset : Expiration | date of the | drug. | (YYYYMMDD) | Freq. Percent Cum. ------------+----------------------------------- 01may1905 | 1 0.01 0.01 22feb2001 | 1 0.01 0.02 30nov2001 | 1 0.01 0.03 01feb2003 | 1 0.01 0.04 04jan2004 | 1 0.01 0.05 05aug2004 | 1 0.01 0.06 31aug2004 | 1 0.01 0.07 30nov2004 | 1 0.01 0.08 31dec2004 | 1 0.01 0.09 01jan2005 | 3 0.03 0.12 12jan2005 | 1 0.01 0.13 31jan2005 | 1 0.01 0.14 01feb2005 | 1 0.01 0.15 28feb2005 | 1 0.01 0.16 01apr2005 | 3 0.03 0.19 30apr2005 | 2 0.02 0.21 01may2005 | 1 0.01 0.22 26jun2005 | 1 0.01 0.23 27jun2005 | 1 0.01 0.24 30jun2005 | 1 0.01 0.25 01jul2005 | 1 0.01 0.26 01aug2005 | 1 0.01 0.27 31aug2005 | 2 0.02 0.29 01sep2005 | 16 0.16 0.45 30sep2005 | 2 0.02 0.47 01oct2005 | 7 0.07 0.54 31oct2005 | 1 0.01 0.55 01nov2005 | 5 0.05 0.60 30nov2005 | 1 0.01 0.61 01dec2005 | 7 0.07 0.68 31dec2005 | 1 0.01 0.69 01jan2006 | 5 0.05 0.74 31jan2006 | 1 0.01 0.75 01mar2006 | 5 0.05 0.80 31mar2006 | 2 0.02 0.82 01apr2006 | 3 0.03 0.85 01may2006 | 1 0.01 0.86 01jun2006 | 1 0.01 0.87 01dec2006 | 2 0.02 0.89 01jan2007 | 2 0.02 0.91 01feb2007 | 1 0.01 0.92 30apr2007 | 1 0.01 0.93 30nov2008 | 1 0.01 0.94 . | 9,906 99.06 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 18 Dec 2015