Summary statistics for nadacc dataset : by Jean Roth , jroth@nber.org , 1 Mar 2018 Variable | Obs Mean Std. Dev. Min Max -------------+--------------------------------------------------------- ndcdescrip~n | 0 ndc | 0 oldnadacpe~t | 1,020,154 3.301334 102.1798 0 20016.17 newnadacpe~t | 1,020,154 3.373188 105.7859 0 20016.17 classifica~g | 0 -------------+--------------------------------------------------------- percentcha~e | 1,020,154 .3469322 18.90807 -98.28 1966.75 percentcha~r | 0 primaryrea~n | 0 startdate | 1,020,154 20485.27 447.0392 19690 21236 enddate | 1,020,154 20492.27 447.0394 19697 21243 -------------+--------------------------------------------------------- effectived~e | 189,545 21113.5 78.64581 20910 21243 year | 1,020,154 2018 0 2018 2018 month | 1,020,154 0 0 0 0 day | 1,020,154 0 0 0 0 by Jean Roth , jroth@nber.org , 1 Mar 2018