Low spam report is Net positive for the forum isn't it? We may be moving to a free-spam Forum. I also had one of the lowest spam report in my section last month.
Unfortunately, there is as much spam as you want today, just look at what is happening in the Gambling board - according to my estimation, at least 25-30% of all posts in that board are pure spam. Members are less and less motivated to report anything, because it is a
"job" that is on a voluntary basis, and there are very few who want to do something without compensation.
Moderation is also a "job" that is on a voluntary basis, the only difference is that we have a custom title and dedicated more time to it.

Back to your statistics; there are reportedly high spam on the gambling board no doubt but going by your percentage 25-30%/100% is below average which means we have way more quality posts on the gambling board overall. If we're being honest, the rate of spam on the gambling board has dropped significantly this year, and the mods are more active now than before.