I think this persentage is more.  Because all the newbies who only work in the bounty keep newbies. I have seen some newbie members whose activity is more than 1000. And those newbie members who participate in the discussion of different boards of the forum do not have to stay newbie for long.  Altimately their rank goes up.

I think Bounty Hunters should at least gain some knowledge about Bitcoin from being active on various discussion of the forum.