Summary statistics for PHYSN_EXT_PRTM_CNT variable in pos2011 dataset :

    Variable |        Obs        Mean    Std. Dev.       Min        Max
-------------+---------------------------------------------------------
PHYSN_EXT_P~ |     37,813    .0050493    .0676648          0       4.53

by Jean Roth , jroth@nber.org , 19 Apr 2019