Until recently it has been impossible, because of the defective registration of vital statistics in the United States, to get figures which show the extent of the problem of urban sterilization. But Dr. Gillette has obtained evidence along several indirect lines, and is convinced that his figures are not far from the truth.[175] They show the difference to be very large and its eugenic significance of corresponding importance. "When it is noted," Dr. Gillette says, "that the rural rate is almost twice the urban rate for the nation as a whole, that in only one division does the latter exceed the former, and that in some divisions the rural rate is three times the urban rate, it can scarcely be doubted that the factor of urbanization is the most important cause of lowered increase rates. Urban birth-rates are lower than rural birth-rates, and its death-rates are higher than those of the latter." Considering the United States in nine geographical divisions, Dr. Gillette secured the following results: RATE OF NET ANNUAL INCREASE _Division_ _Rural_ _Urban_ _Average_ New England 5.0 7.3 6.8 Middle Atlantic 10.7 9.6 10.4 East North Central 12.4 10.8 11.6 West North Central 18.1 10.1 15.8 South Atlantic 18.9 6.00 16.0 East South Central 19.7 7.4 17.8 West South Central 23.9 10.2 21.6 Mountain 21.1 10.5 17.6 Pacific 12.6 6.6 9.8 ---- ---- ----- Average 16.9 8.8 13.65 Even though fuller returns might show these calculations to be inaccurate, Dr. Gillette points out, they are all compiled on the same basis, and therefore can be fairly compared, since any unforeseen cause of increase or decrease would affect all alike. It is difficult to compare the various divisions directly, because the racial composition of the population of each one is different. But the difference in rates is marked. The West South Central states would almost double their population in four decades, by natural increase alone, while New England would require 200 years to do so.