Amanda isn't really common in Germany at all. It never got as popular here as it was in the US. I only know of one Amanda (around four years old) whose parents pronounce her name the English way. I would guess most Amandas are either very young (under 12) or pretty old. It was on #417 in 2008. The only other chart entry I can find is in the 1890s at #52 and in the 1900s when it was #77.