Frequencies for first 10,000 rows of dmage variable in natl1974 dataset : Age of | Mother | Freq. Percent Cum. ------------+----------------------------------- 12 | 4 0.04 0.04 13 | 16 0.16 0.20 14 | 59 0.59 0.79 15 | 195 1.95 2.74 16 | 398 3.98 6.72 17 | 570 5.70 12.42 18 | 696 6.96 19.38 19 | 774 7.74 27.12 20 | 823 8.23 35.35 21 | 744 7.44 42.79 22 | 703 7.03 49.82 23 | 654 6.54 56.36 24 | 651 6.51 62.87 25 | 650 6.50 69.37 26 | 555 5.55 74.92 27 | 530 5.30 80.22 28 | 337 3.37 83.59 29 | 298 2.98 86.57 30 | 250 2.50 89.07 31 | 203 2.03 91.10 32 | 179 1.79 92.89 33 | 145 1.45 94.34 34 | 120 1.20 95.54 35 | 102 1.02 96.56 36 | 72 0.72 97.28 37 | 62 0.62 97.90 38 | 55 0.55 98.45 39 | 36 0.36 98.81 40 | 49 0.49 99.30 41 | 25 0.25 99.55 42 | 23 0.23 99.78 43 | 8 0.08 99.86 44 | 7 0.07 99.93 45 | 4 0.04 99.97 46 | 1 0.01 99.98 47 | 2 0.02 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 3 Jan 2016