How much money does Anime net for Japan and why?

That kind of thing is rather hard to quantify.  Anime is deeply
ingrained in Japanese culture, it would be like asking how much does
all broadcast and cable TV shows net for the United States, and why.

Isn't it the toned down version of japanese cartoon porn - the "under
age" variety (designed for grown men - with damaged minds)that would
explain it's popularity & Ecomomic clout.

Whistlefisher-ga, anime is the Japanese word for animation, and is NOT
porn.  Hentai is porn.  Hentai.  Anime.  Different ;).  There are
girly animes, hardcore rockstar animes, superhero animes, and yes,
even perverted animes.  Think of any genre or situation possible to
produce and there is more than likely an anime on it...

Anime is basically the whole Japanese cartoon industry. As someone
just said the word "anime," is just a borrowed cut down word short for
meaning animation.

Going back to the original question, to maybe help you get a few
numbers, your going to have to research and find out names of diffrent
companies who create and distribute anime in Japan.

However, in Japan many people watch Anime, including adults. Though,
of course there is other programing. In one american magazine called
"Newtype," (just borrow one it cost around 12.95) you can see what's
currently playing in Japan right now (anime-wise).