It's around 55–60% of immigrants who come from Spanish-speaking countries.
Also, this uses official numbers, which reflect a larger Spanish speaking share than there is in reality (as people from Spanish-speaking countries have more straightforward visa processes).
So the real percentage is probably much lower (as there are a lot of undocumented migrants. 1.2 million applied for "legalization").
Japan has an aging problem and a big misogyny problem too.
Say, I heard France has great cuisine, but I had street food in Paris and it was meh.