152 BUREAU OF AMERICAN ETHNOLOGY [Bull. 197 



Footnotes to table 29, continued. 



"' From the files of the U.S. Public Health Service, Window Rock, Ariz. Through the courtesy of Dr 

 James E. Bondurant, area health director. 



13 Young, 1956, p. 154. The data for the years 1944 through 1948 are also presented in Bureau of Indian 

 Affairs, 1950, and Felsman, 1951. The data for the years 1948 through 1952 were also compiled by Drs. 

 Robert Smith, Clarence Salsbury, and Alexander Gilliam with the assistance of J. Nixon Hadley and 

 Francis Felsman, and are in Smith et al., 1956. 



" Young, 1958, p. 339. The population totals given for the years 1955 and 1956 were obtained by taking 

 the average of the number derived from the reported number and rate of births and the number derived 

 from the reported number and rate of deaths for the given year. The population total for 1957 is the estimate 

 of tlie U.S. Public Health Service, Division of Indian Health, Albuquerque OflQce, as of July 1, 1957. 



the base population is small, considerable variation in vital rates 

 could be attributed to chance factors. However, where the births and 

 deaths are reported in round numbers, these numbers are at best crude 

 estimates and at worst, purely fictitious. 



The average annual rates of natural increase that are derived from 

 reported Navaho population totals at selected years are useful in 

 interpreting the statistics on reported births and deaths, since they 

 reflect the underlying dynamics of Navaho population growth at 

 difl'erent periods in the past. Although these average annual rates 

 are themselves subject to considerable variation because of uncertainty 

 with respect to the total number of Navahos at any given time, it is 

 possible to establish a range of plausible rates of natural increase for 

 different periods. Given an approximate rate of natural increase, it is 

 possible to indicate plausible combinations of crude birth and crude 

 death rates which might account for the indicated increase. 



On the basis of the data given in table 30 the following range 

 of probable growth rates can be suggested : For the period from 1870 

 to 1900, the average annual rate of natural increase appears to lie 

 somewhere betw^een 1.5 and 2.0 percent; for 1900 to 1930 the rate 

 appears to lie between 1.75 and 2.25 percent; for 1920 to 1950 the rate 

 appears to lie between 2.4 and 2.8 percent; and for the period since 

 1950 it appears to lie between 2.4 and 3.3 percent. 



It is possible to infer a very wide range of vital rates which, in 

 combination, would produce rates of increase w^hich fall w^ithin the 

 above ranges. For example, for the period 1870 to 1900, a crude birth 

 rate of 40 and a crude death rate of 20 per 1,000 would produce a crude 

 rate of natural increase of 2 percent per year. By contrast, a crude 

 birth rate of 50, in combination with a crude death rate of 35 per 1,000, 

 would produce a crude rate of natural increase of 1.5 percent per year. 

 Either set of assumptions would be consistent with the assumed range 

 of natural increase for this period.^ 



3 No claim is made for the accuracy of the vital rates that are postulated in this analysis. 

 Their sole intended function is to illustrate the extreme unreliability of the reported vital 

 data on the Navaho population. In postulating these ranges, however, an attempt has been 

 made to approximate the most plausible magnitudes for the different periods. The reader 

 should note, for example, that the postulated rates of natural increase are supported by 

 the general trends in reported Navaho population totals at different times. Similarly, the 

 minimum postulated crude birth rate of 40 per 1,000 is supported by the fact that the 

 reported crude birth rate for the Navaho population in 1956 and 1957 approaches this 

 figure. If we assume that Navaho births are not yet completely registered, and that 



