due to a combination of unrecorded immigration (using the 1931 census report estimate) and undercounting in the 1922 census. While noting the uncertainty of earlier data, Bachi also observed that the Muslim population growth in the 19th century appeared to be high by world standards: "[B]etween 1800 and 1914, the Muslim population had a yearly average increase of an order of magnitude of roughly 6–7 per thousand. This can be compared to the very crude estimate of about 4 per thousand for the "less developed countries" of the world (in Asia, Africa, and Latin America) between 1800 and 1910. It is possible that some part of the growth of the Muslim population was due to immigration. However, it seems likely that the dominant determinant of this modest growth was the beginning of some natural increase." According to Justin McCarthy, "... evidence for Muslim immigration into Palestine is minimal. Because no Ottoman records of that immigration have yet been discovered, one is thrown back on demographic analysis to evaluate Muslim migration." McCarthy argues that there is no significant Arab immigration into mandatory Palestine: From analyses of rates of increase of the Muslim population of the three Palestinian sanjaks, one can say with certainty that Muslim immigration after the 1870s was small. Had there been a large group of Muslim immigrants their numbers would have caused an unusual increase in the population and this would have appeared in the calculated rate of increase from one registration list to another... Such an increase would have been easily noticed; it was not there. The argument that Arab immigration somehow made up a large part of the Palestinian Arab population is thus statistically untenable. The vast majority of the Palestinian Arabs resident in 1947 were the sons and daughters of Arabs who were living in Palestine before modern Jewish immigration began. There is no reason to believe that they were not the sons and daughters of Arabs who had been in Palestine for many centuries. McCarthy also concludes that there was no significant internal migration to Jewish areas attributable to better economic conditions: Some areas of Palestine did experience greater population growth than others, but the explanation for this is simple. Radical economic change was occurring all over the Mediterranean Basin at the time. Improved transportation, greater mercantile activity, and greater industry had increased the chances for employment in cities, especially coastal cities... Differential population