Learn Japanese vocabulary while you work (just push play) (locserendipity.com)

Some people have an interest in the country and the culture. For them, knowing Japanese isn't useless. Anyway, not everything you learn or know needs to be practical. Nothing wrong with doing something because you enjoy it, regardless of whether or not there's any professional benefit/use.

I'd like to see the source of your very dubious statistic. Or is it just that a knowledge of Japanese is useless to you?