As an illustration of the method of reckoning the gain or loss in population, let us take the year 1910. In that year there were 1,041,570 immigrant aliens, and 156,467 nonimmigrant aliens admitted, making a total of 1,198,037. There were 202,436 departures of emigrant aliens and 177,982 of nonemigrant aliens, making a total of 380,418. Thus there was a net gain in the year of 817,619 aliens all together. But not all of these were permanent residents. To get an idea of the actual increase of permanent residents we need to add together two classes,—the immigrant aliens, who come here for the first time with the intention of residing permanently, and those nonimmigrant aliens who are such, not because they do not expect to reside here permanently, but because their permanent residence has already been established here and who have been abroad for a brief period. Of the former class, the immigrant aliens, there were 1,041,570; of the second class, nonimmigrants whose places of last permanent residence and of intended future residence were both the United States, there were 94,075. This makes a total of 1,135,645 permanent alien residents who came into the United States in the year in question. The actual decrease in permanent residents may be computed in a similar way. In the year in question there were 202,436 emigrant aliens who departed, and 89,754 nonemigrant aliens whose places of last permanent residence and intended future residence were both the United States,—that is, permanent residents of this country who left for a brief period only. This makes a total of 292,190 permanent residents of this country who left it in the year in question. Subtracting this number from the total of permanent residents who arrived, we have a remainder of 843,455. This represents the actual gain in permanent alien residents during the year in question. This figure, in the year in question, happens to come very near to the gross gain estimated in the simplest way. But it is not necessarily so, and in the year 1908 there was considerable difference between the two figures. It is not always necessary to make this somewhat involved calculation. In many cases, the mere comparison of the figures for immigrant and emigrant aliens is sufficient for the purpose. But there are many other instances in which accuracy and consistency require this exact calculation to be made, and it is a decided acquisition to the study of immigration to have these data available.[110] Thus in the year 1909 the net gain in permanent alien residents was 584,513, while in 1908 it was only 341,075; yet there were more immigrant aliens admitted in 1908 than in 1909.