Interesting stats and unlikely to deter the spammers unfortunately, quite the opposite.
I hope Steemit put in some kind of automated checker at some point as it starts to get really frustrating when you want to really engage with people and you have to read through half a dozen or more of these the get to the real comments nestled in between.
I guess if downvotes didn't use up one's power these graphs would look a little different!
One other thing I have noticed is that new users quite often think these comments are legitimate and thank the damn spammers!!
True, but can you imagine the abuse of flags were 'free'?!
Yes others have mentioned this, and you can't blame the newer users for appreciating even a short comment.
Good point about the down votes.
Something will have to be done though otherwise you wan't be able to see the legitimate comments for all the spam as the site gains more users.
Its a work in progress and recent reports suggest that the battle is slowly being won, although it will remain a war of attricion for a while I think. Cheers!