delivered the opinion of the court,
If the case stated contained an unqualified admission or averment of fact that at the time plaintiff entered on his official duties as Recorder of Deeds in Luzerne county, the population of the county was over one hundred and fifty thousand and less than two hundred and fifty thousand, there might be something on which to base a judgment in his favor; but, there is no such admission or avermeut therein. The averment in the second paragraph, “That in 1880, when the last decennial census was taken, the population of Luzerne county was one hundred and thirty-three thousand and sixty-six,” is distinct and positive, but the succeeding averment, viz: “and when plaintiff entered on his official duties the population of Luzerne county was over one hundred and fifty thousand, and less than two hundred and fifty thousand, based upon the rea*571sons incorporated in the following paragraph,” is obviously a mere inference of fact from the data contained in the third paragraph of the case stated. The inference thus drawn from the facts, embodied in that paragraph, may possibly be correct, but it is wholly unwarranted. It is at best only a method of forming an approximate estimate. The only legally recognized method of determining the poptilation of any particular county or district is by resorting to the last preceding decennial census ; and, according to that the population of Luzerne county is less than one hundred and fifty thousand. We do not say it is not competent for the Legislature to provide some other or additional mode of determining the fact; but, until some other legal provision is made, we must be governed by the only recognized rule applicable to the subject. In Luzerne County v. Griffith, 1 Kulp, 297, this court said: “In the absence of express legislative declaration of the fact, or of any other method provided by the Legislature for ascertaining it, the last preceding decennial census is to be resorted to as the best evidence of the population of a county in case of classification of counties by population.”
In the light of existing legislation, we have no doubt that for the purposes of classification under the various Salary Acts, each county must, remain in the class in which the last census found it until it is transferred to another class by a subsequent census. The United States decennial census is the only official determination of population that we now have; and the inconvenience and injustice that would necessarily arise from accepting any ,unofficial guide to the classification of counties, for salary purposes, cannot well be overestimated. Legislative and judicial apportionments are both based on population determined by the last preceding census. The Constitution provides that “ whenever a county shall contain forty thousand inhabitants it shall constitute a separate judicial district; but, in Commonwealth ex rel. Chase v. Harding, 6 Norris, 851, we held that such separate districts can only be formed after a decennial census showing the requisite population. The cases, it is true, are not exactly parallel, but the analogy is very close.
The radical error committed by the learned judge of the Common Pleas was in assuming the case stated contained an unqualified admission that the county contained a population of over one hundred and fifty thousand when plaintiff below entered on the duties of his office. This was a mistake. It contains no such admission. The statement as to population at that date, as we have already noticed, is at best but a mere inference of fact drawn from other facts which are assumed to be true. To sanction such a mode of determining population *572at any given time would lead to interminable trouble and confusion. The question, as to the manner of ascertaining what the population of a county is, did not arise in Monroe v. County of Luzerne, 7 Out., 278. The present Chief Justice, delivering the opinion of the court in that case, saj^s: “By what mode that population shall be ascertained does not arise in this case. The agreement of the parties settles several questions relating to the population. We therefore take that agreement as the starting point.” The question, in that case, grew out of the erection of Lackawanna county in 1878, and does not rule the point upon which this ease turns. In that case the facts in regard to the population in the respective parts composing the old and the new county were distinctly stated' as they appeared by the census of 1870.
Judgment reversed, and now judgment for defendant below on the case stated.