Frequencies for ptype variable in impact2015 dataset : Provider | Type | Freq. Percent Cum. ------------+----------------------------------- 0 | 2,622 75.43 75.43 7 | 193 5.55 80.98 8 | 32 0.92 81.90 16 | 326 9.38 91.28 17 | 124 3.57 94.85 21 | 1 0.03 94.88 22 | 1 0.03 94.91 . | 177 5.09 100.00 ------------+----------------------------------- Total | 3,476 100.00 by Jean Roth , jroth@nber.org , 16 Dec 2016