Ti chiedi quale sarebbe un numero simile per la Germania? “…l’immigrazione rappresentava il 25% del PIL pro capite spagnolo e il 10% delle entrate della previdenza sociale, ma solo l’1% della spesa pubblica”

From what I can see, the quote comes from Pedro Sanchez, but he hasn’t clarified what he means by these figures, so it’s impossible to construct an analogous statement about Germany. If one wanted to make such a statement, an in-depth study would have to be conducted, as many many effects of immigration would have to be considered even if you have a specified scope.