Frequencies for first 10,000 rows of dmage variable in natl1980 dataset : Age of | Mother | Freq. Percent Cum. ------------+----------------------------------- 12 | 1 0.01 0.01 13 | 10 0.10 0.11 14 | 51 0.51 0.62 15 | 144 1.44 2.06 16 | 268 2.68 4.74 17 | 465 4.65 9.39 18 | 541 5.41 14.80 19 | 638 6.38 21.18 20 | 720 7.20 28.38 21 | 740 7.40 35.78 22 | 771 7.71 43.49 23 | 703 7.03 50.52 24 | 656 6.56 57.08 25 | 647 6.47 63.55 26 | 600 6.00 69.55 27 | 548 5.48 75.03 28 | 467 4.67 79.70 29 | 418 4.18 83.88 30 | 377 3.77 87.65 31 | 284 2.84 90.49 32 | 238 2.38 92.87 33 | 190 1.90 94.77 34 | 118 1.18 95.95 35 | 105 1.05 97.00 36 | 83 0.83 97.83 37 | 77 0.77 98.60 38 | 35 0.35 98.95 39 | 39 0.39 99.34 40 | 22 0.22 99.56 41 | 22 0.22 99.78 42 | 12 0.12 99.90 43 | 2 0.02 99.92 44 | 3 0.03 99.95 45 | 2 0.02 99.97 46 | 2 0.02 99.99 47 | 1 0.01 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 3 Jan 2016